[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/helix350195_9684.png]]
[[caption-width-right:350:[[ScaleOfScientificSins Play God]]. [[EquivalentExchange Pay The Price]].]]

''Helix'' is a 2014 Creator/{{Syfy}} Original Series, centering around Dr. Alan Farragut (Billy Campbell) and his team of CDC staff who have been dispatched to an arctic private research facility, Arctic [=BioSystems=], to contain an unknown virus. Farragut and his team must contend with both the unknown pathogen and unforthcoming scientists reluctant to disclose the virus' origin or its basis in their unregulated research. Matters worsen when Alan's brother Peter, one of the first research scientists infected, escapes from isolation, while Alan's team begins to realize that TheVirus not only grants SuperStrength, but rewires its victims' brains to become a "[[NotUsingTheZWord perfect contagion machine]]."

And that's just the beginning of the problems that Farragut and his team encounter. Arctic [=BioSystems=] is ''the'' cutting edge biological research facility, where humanity's greatest minds take advantage of the isolation - both environmental and legal - to perform the most dangerous of experiments in pursuit of the impossible - and the unthinkable. With stakes this high, everyone has their own agenda - including [[MysteriousPast him and his team]].

While heavily advertised before its premiere as a fairly realistic horror series, or at least with some grounding in real-life science, halfway through its first season (around episode 7) ''Helix'' undergoes a drastic GenreShift, centering around the virus actually being an element in a centuries-spanning conspiracy being conducted by immortal meta-humans. Basically it was promised and framed as Creator/JohnCarpenter's ''Film/TheThing1982'', but quickly turned into a ''Franchise/ResidentEvil''-style mashup - then at the end of Season 1, after so much buildup surrounding the arctic facility, they blow it up, and Season 2 moves to a remote island in the Pacific Northwest. By mid Season 2 it barely resembles what it was initially marketed as. TheChrisCarterEffect was also strongly in play.

The show was canceled shortly after the end of its second season. According to Aintitcool.com's report, the ratings were abysmal - so low, in fact, that they were ''below the threshold'' at which ratings can even be nationally measured.
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!!This series provides examples of the following:

* AbusiveParents: The Farragut brothers had an angry, violent drunk for a father, which, according to Alan, lies at the root of some of Peter's behavioral tics, even when infected.
* ActionSurvivor: Of the main ensemble, only Major Balleseros and security head Daniel have anything in the way of combat training. The rest are scientists, wholly unprepared for aggressive {{Plague Zombie}}s, and tend to survive through luck and quick thinking.
* TheAgeless: [[spoiler:Hatake and the board of Ilaria Corporation are a group of immortals from the 1500s. However, despite their longevity, they can still be destroyed by most things that would kill an ordinary human, such as decapitation.]]
* AirVentPassageway: Used by Peter to make his way around the facility. {{Lampshade|Hanging}}d by Major Balleseros during an attempt to trail Peter:
-->'''Balleseros''': "Now I know what a TV dinner feels like."
-->'''Alan Farragut''': Didn't think you were old enough to remember that one.
-->'''Balleseros''': ''Film/DieHard''? Sure, saw it in third grade.
-->'''Alan Farragut''': ''Ouch.''
* AlcoholicParent: The Farragut brothers' {{abusive|parents}} father, who, as detailed in "Single Strand," was so often drunk that Peter would regularly rifle through his pockets and offer to split their contents with Alan.
* AllThereInTheManual: Supplemental material is available at Syfy's Helix [[http://www.syfy.com/helix website]], particularly the [[http://www.syfy.com/accessgranted/helix Access Granted]] subsection, which contains in-universe personnel files, video resumes, and cryptic documents.
* AlliterativeName: Dr. Hiroshi Hatake, head researcher and MorallyAmbiguousDoctorate at Arctic Biosystems
* AlmostOutOfOxygen: {{Invoked|Trope}} In "Single Strand," by a few of the quarantined in level R who decide to override the base's oxygen scrubbers to force Hatake to negotiate.
* AmericaSavesTheDay: In the pilot, this is {{Lampshade|Hanging}}d by Dr. Sarah Jordan when she points out to their army liaison that neither the CDC nor USAMRIID should have jurisdiction over Arctic Biosystems, as it's in international territory. Major Balleseros {{handwave}}s this away, noting they've been allowed temporary access as the first to receive the distress call.
* AncientConspiracy: [[spoiler: The Ilaria Corporation is a front for a group of immortals that have been plotting to TakeOverTheWorld for half a millennium.]]
* AngerBornOfWorry: {{Downplayed|Trope}}. For the first two days of the mission, Alan needlessly bickers with ex-wife Julia while pulling rank as mission lead and dictating where Julia focuses her efforts. He later apologizes and reveals that he's snappish because he feels he can't protect her from TheVirus if he doesn't know her whereabouts. She chides him mildly, but it's made clear that, in their brief time together, he's reignited his [[OldFlame old torch]].
* AnimalTesting: Animal testing is treated as expected and practical, to the point where Doreen becomes suspicious that staff claim ''not'' to use monkeys, which would be necessary given their research. The CDC researchers must use lab rats to test pathogens. Yet, after the missing monkeys are discovered, a researcher refers to their infection with SyntheticPlague as "an abomination," while Doreen herself points out expressions of fear on their frozen corpses, to show that, compared to the {{Science Hero}}es, the {{Morally Ambiguous Doctorate}}s have gone too far.
* AnimalsLackAttributes: {{Justified| Trope}} in-universe, the base's lab rats have no sex organs, which perplexes Doreen when she examines one and can't tell if it's male or female.
* AnArmAndALeg: In the pilot, a security team member is killed and his lower arm is severed when [[spoiler: Peter decides he needs a BorrowedBiometricBypass to infect other research scientists]].
* ApocalypseHow: [[spoiler:Constance wants to engineer a Societal Disruption through the NARVIK-A strand, then rule the survivors.]]
** As of Season Two, [[spoiler:thirty years in the future, an outbreak of TXM7 has wiped out most of the world's population centers, and even immortals are becoming infected.]]
* ArmiesAreEvil: Balleseros' cryptic conversations with Hatake and blatant sabotage imply the SyntheticPlague is government-funded, and he's been sent to help keep it secret at any cost. In spite of this, he's out of the loop enough to be taken aback when he stumbles onto a group of frozen monkey corpses.
* ArtisticLicenseAnimalCare: In the pilot, Doreen is a veterinary pathologist, but does not make an effort to ''set a nonlethal trap'' for an escaped lab monkey that is very likely to be agitated, fearful and prone to jumping, whether or not it's infected with TheVirus. Instead, she hopes to catch it with her ''bare hands.'' It's no surprise that it attacks her, and she's incredibly lucky not to be scratched or bitten.
* ArtisticLicenseBiology: Frequently, in spite of the attempt to ground {{Plague Zombie}}s in epidemiology, using fictional CDC employees.
** The CDC team accepts injected RFID chips from a shared device. This is risky, considering that this could be a method of transmission of TheVirus, and they don't know who are asymptomatic carriers, including the device's handler.
** Arctic Biosystems' {{designer|Babies}} lab rats, who lack sex organs so they're more docile, are a solution in search of a problem. Lab rats are already docile, and removing sex organs removes both avenues of study (effects on reproduction, etc) and ability to compare or extrapolate from research on non-customized rats.
*** Also, a rat without sex organs shouldn't look any different from a female upon external inspection.
** Less than a day is insufficient time to determine, via rat observation, if TheVirus is airborne. Even if true this shouldn't be cause to remove a HazmatSuit, as it could be absorbed through the skin, and bodily fluids can aerosolize.
** Mutagens are, in and of themselves, not so disturbing to work with as Julia and Hatake say. They're used in cell biology.
** Alan is frightened that an infected Peter will be killed by halothane gas, and wants him alive because he may have developed antibodies. That takes five days, while Peter's had TheVirus for three.
** Viruses are not typically searched for by shape, and when Julia says she's searched for all of them, "''even'' icosahedrons" she's treating the most common shape as though it were unexpected.
** The Zeiss phase-contrast microscopes depicted can't produce such animated images, much less show a virus that's smaller than usual (viruses also don't move like protozoa). They'd need electron microscopes to see such small objects.
** In "Vector", Julia says rabies "doesn't include a compulsion to spread the disease", but that's ''exactly'' how rabies works. This error is odd since Peter's first symptoms are a supernatural exaggeration of rabies. His frightened refusal of water mirrors its hydrophobia, and the neck pulsations evoke the painful throat spasms that happen after those with rabies try drinking. It would have been more accurate to says that rabies does not include higher reasoning like deduction and complex tactics.
** Isolation and safety protocols are more talked about in the abstract than abided by. Isolation facilities should be larger and more secure given Arctic Biosystems extensive work with pathogens. In "Vector", Dr. Bryce is correct that he and Sulemani should be separated from the sicker Haven, since late stage infectees are super strong and violent. In "274", Daniel is likewise correct when he thinks the now-symptomatic Sulemani and Bryce should stay isolated from the asymptomatic in quarantine, and Alan's failure to account for this results in Bryce and Sulemani's deaths.
** By the same token, the fact that they move down from full Hazmat to simple face masks is extremely poor judgement, given the strength, speed, and determination of the Vectors to spread the infection. "274" shows that they can be slipped off relatively easily, and infection is a death sentence no matter which strain is contracted. Worse still, even face shields aren't employed consistently.
** In "274", the failure of the rapid response test is almost a ForegoneConclusion, given that Sarah sampled too few people to be assured of its efficacy, even given a limited population and time frame to work with.
** Down in the samples vault Alan finds a vial of Yersinia Pestis, and identifies it as the Black Death, or bubonic plague, with a note of complete dread in his voice. He seems to be reacting as if the Bubonic Plague is a apocalypse level disease, when in reality bubonic plague is now treatable with antibiotics. There are still outbreaks happening to this day, and while it is deadly, the death toll of the most recent outbreak ran at around 7% of infectee’s. The only reason it was so deadly in the 14th century is because there was no understanding of bacteria, let alone antibiotics or, you know, basic hygiene.
*** They also name drop the Plague of Justinian, which was a biblical pandemic. It has now been found to be another outbreak of Bubonic Plague, the aforementioned Yersinia Pestis. So it makes very little sense to store two samples under different names unless you’re being dramatic.
* ArtisticLicenseEngineering: Several design elements of Arctic Biosystems are infeasible or unwise given its location. According to the map in the pilot, the base is in the Arctic Ocean with no landmass to anchor it, despite its many [[ElaborateUnderGroundBase underground levels]]. It also shouldn't have survived being seated in ice for so long, as instability and constant movement would gradually crush it, in the same way many incarnations of the Antarctic [[http://en.wikipedia.org/wiki/Halley_Research_Station Halley Research Station]] were. It's depicted as having solar power generation (solar panels would likely be rendered ineffective or crushed by snow) and horizontal-shaft wind turbines which easily freeze and are inoperable in high winds.
* ArtisticLicenseGeography:
** Arctic Biosystems is "above the 83rd parallel" which is treated narratively as a kind of no-man's land of international territory, freeing it from governmental scrutiny. But in reality, its location would probably subject the ResearchInc to significant attention from an intergovernmental body with vested interest in monitoring it: the [[http://en.wikipedia.org/wiki/Arctic_Council Arctic Council]] (of which the U.S. is a member country) and an affiliated NGO: the [[http://en.wikipedia.org/wiki/International_Arctic_Science_Committee International Arctic Science Committee]].
** Being above the 83rd parallel, and taking place [[AllThereInTheManual entirely in January 2014]], the base should not be routinely experiencing blazing daylight, but rather a [[TheNightThatNeverEnds fairly long]] [[http://en.wikipedia.org/wiki/Polar_night polar night]].
** In season 2, St. Germain [[CaliforniaDoubling looks]] rather [[UsefulNotes/TheOtherRainforest temperate]] for an island located south of Costa Rica.
* ArtisticLicenseMedicine: The very fact that Alan and Julia accepted a mission that would involve treating a brother and an ex-lover, respectively, is a massive conflict of interest, special request for Julia's presence or no, particularly since neither could be expected to make necessarily detached decisions with their respective histories. It is at least called attention to.
* ArtisticLicensePhysics: In the pilot, Major Balleseros claims that "freezing rearranges tensile strength," confusing tensile strength for ''molecular'' strength.
* AsceticAesthetic: Parts of the base are sleek, modernist and spare to the point of creepiness. Some promos {{Exaggerate|d Trope}} the contrast, showing BadBlackBarf dripping on stark white modernist furniture and walls.
* BadBlackBarf: Vomited by the infected into the mouths of their victims in order to transmit TheVirus. Peter often has rills of black mucus at the corners of his mouth, to the point where spatters of it mark his trail around the base.
* BilingualBonus[=/=]ShoutOut/ToShakespeare: In a video on the [[http://www.syfy.com/accessgranted/helix Access Granted]] website, we see the [[WhatHappenedToTheMouse whereabouts]] of the third "runner" from Peter's attack, Dr. Raver, while Hatake's voice recites a monologue in Japanese. When translated, it is the "What a piece of work is man" speech, from ''Theatre/{{Hamlet}}''
* BioluminescenceIsCool: {{Discussed|Trope}} in "274" when Sarah shows Julia her bright idea for a rapid response test: Using bioluminescent crystal jellyfish proteins so that a positive test emits a SicklyGreenGlow.
* BlackBlood: {{Justified|Trope}} as a marker of infection with TheVirus, and easily visible through TaintedVeins.
* BodyInABreadbox: In the pilot, Alan finds that Peter has killed a luckless security tech, stripped his clothes and squirreled his corpse away in an {{Air Vent| Passageway}}.
* BoomHeadshot: In "274," Alan is forced to kill an infected Sulemani this way, shooting her with Daniel's gun as she charges Julia.
* BorrowedBiometricBypass: In the pilot, knowing his RFID chip is deactivated, Peter finds a workaround to get into a lab and infect others [[spoiler:via the severed arm of one of the security guards, which contains a valid RFID chip]].
* BrainwashedAndCrazy: TheVirus has incredibly "focused behavioral patterns" that cause its victims to behave in this way, as they are compelled to spread the contagion. Though violent and paranoid, Vectors are also cognizant enough to form plans to access uninfected, like Peter, who manages to find a workaround for a biometric lock.
* BrotherSisterIncest: [[spoiler: Amy and Landry]], it turns out, have the same mother, making their "fun" this.
* CellPhonesAreUseless: The arctic location of the research base precludes normal cell phone use. Arctic Biosystems has a state of the art satellite communication system with 10 gpbs, but it only functions for an hour each day. Then it's sabotaged.
* CleanUpCrew: {{Implied|Trope}} in "274". Doreen and Balleseros are convinced one of these, under Hatake's direction, has made off with Doreen's dissected monkey corpse, particularly since her necropsy lab appears to have been scrubbed with formaldehyde.
* ClosedCircle: Several factors conspire to keep the CDC rapid response team at Arctic Biosystems. It's CDC protocol to achieve full containment of a pathogen before leaving, the helicopters that transported them can't stay, due to the HostileWeather's ability to coagulate fuel, and satellite communication to the outside world, though instantaneous, is only active for an hour a day. Then the satellite is sabotaged.
* ComputerVoice: Arctic Biosystems has a neutral, not unpleasant female voice that makes periodic announcements and status alerts, including when Peter breaks out of isolation, and also announces the PreviouslyOn segment.
* ContaminationSituation:
** The series begins in the immediate aftermath of Dr. Peter Farragut's infection with a SyntheticPlague, turning him into PatientZero and the ensemble's TragicMonster, a carrier of TheVirus who spreads it throughout the research base where he works. The CDC rapid response team includes his brother Alan and his ex-lover Julia, both of whom want to see him saved despite interpersonal tensions and shared estrangement.
** Peter soon infects Julia, and she has to cope with realizing her fate and being the sole CDC member in quarantine with other infected.
* ConverseWithTheUnconscious: In "274" Julia talks to the heavily sedated Peter about her inability to handle the mixed emotions and memories that have been dredged up when she sees him.
* CureForCancer: In "Aniqatiga", Hatake claims that this is what his team of scientists were trying to develop [[GoneHorriblyWrong but it didn't work out so well]] and they ended up inadvertently creating TheVirus instead. It's clear he's lying through his teeth, though.
* CutApart: Played with in "San Jose". Julia and a CDC expedition consisting of Sarah, Peter and Kyle arrive on the island separately. After Julia has been captured by a mask-wearing native and is about to be tortured, her former friends are just about to burst into the building where she's apparently been kept, only to find an empty room. The thing is, it ''is'' the exact same building: the actual reveal is that [[FlashForward these events are set 30 years apart]], as demonstrated by a transition shot of the sped-up decomposition of an animal corpse over that period (Julia, being immortal, would have shown no signs of aging during that time period).
* CutPhoneLines: In "274," when he hears Alan's intent to call the army in for backup, Balleseros blows up the satellite and communications system so Arctic Biosystems is both cut off from the outside world, and its intrabase phone lines disconnect.
* DeadlyGas:
** In the pilot, Alan is frightened that the KnockOutGas released in the air vents will have this effect on the infected Peter. He needn't have worried, the halothane [[SubvertedTrope doesn't faze]] Peter at all.
** In "274" Doreen has to release this in the observation box to stop the rapid growth of viral MeatMoss from an infected monkey blood sample.
* DeadlyLunge: Standard M.O. for infected animals and humans, to get close enough to victims to vomit BadBlackBarf into their mouths and transmit TheVirus.
* DecontaminationChamber: Both depicted and merely inferred between scene changes. In particular Julia is caught and infected by Peter while she's taking a shower as part of decontamination procedures in "Vector."
* DefectorFromDecadence: Hatake used to be part of the [[spoiler: group of immortals]] controlling Ilaria Corp., but parted ways with them due to disagreeing over their ultimate goal of [[spoiler: ruling the world]].
* DefinitelyJustACold:
** Early in the mission, Sarah begins to exhibit a hand tremor, which Julia incorrectly interprets as a symptom of infection until Sarah tests herself. Sarah blames fatigue, and the viewer is likely to attribute it to delayed fear reaction from a trauma-filled day. But in "274" she pops pills in her quarters, and reveals a large vertical scar on her back. "Single Strand" reveals the actual cause to be a tumor, and reveals her pills as gabapentin (an anticonvulsant[=/=]painkiller), so she likely has epilepsy as a result of a brain tumor.
** In "274," after being infected by Peter, Julia goes into denial and tells Alan she fainted in the shower due to fatigue, later projecting and accusing Sarah of being a ZombieInfectee herself.
* DesperateObjectCatch: Played with in the pilot, when Alan tosses a vial of what he ''claims'' is cholera to the new CDC recruits to impress upon them the sort of risks they'll face if they aren't scrupulously careful. He later admits that it's just scotch in the vial.
-->''Single malt. In fact, [[INeedAFreakingDrink toss it back]].''
* DiegeticSwitch: In "Vector," an [[SoundtrackDissonance easy listening]] piece goes from slightly muted, tinny SourceMusic played over speakers to clear BackgroundMusic while Julia encounters and then is attacked by Peter while showering during decontamination.
* DistressCall: Arctic Biosystems sends one that's intercepted by a military listening post, reporting an outbreak of TheVirus and specifically requesting the aid of the CDC's Dr. Julia Walker, which kicks off the plot.
** Alan and Julia send an SOS from a nearby abandoned satellite station in "Fushigi". They receive a reply but are attacked and the radio destroyed before they can follow up with details.
* DramaticChaseOpening: The opening scene of the pilot intercuts the slow, walking pursuit of HazmatSuit-clad Hatake and Aerov with the panicked running of an infected Peter, presumably escaped from isolation, barreling down hallways and trying to hide in a lab, only to be dragged off screen by a fellow infected. Hatake and Aerov eventually discover a prone, exhausted Peter a short distance away from two infected human corpses.
* EerieArcticResearchStation: The first season is entirely set inside a massive Arctic research station where a viral outbreak at the base requires intervention from CBC officials. However, even they are unable to deal with the situation when the virus starts transforming people into ravenous {{Technically Living Zombie}}s. The whole thing is slowly revealed to be part of a [[spoiler:conspiracy by a secret society of immortals to develop a plague to wipe out humanity.]]
* ElaborateUndergroundBase: Arctic Biosystems has ''several'' subterranean levels.
* EmotionalMaturityIsPhysicalMaturity: [[spoiler:Hatake mocks the Scythe for this; despite the fact that both are over five centuries old, the Scythe was made immortal while still a teenager and still kinda acts like it in spite of his best efforts.]]
* EnclosedSpace: Arctic Biosystems, an isolated arctic research base.
* TheEngineer: The CDC's army liaison, Major Balleseros, is a systems engineer whose job it is to analyze the facility itself to discern structural methods of transmission.
* FaceHeelTurn: [[spoiler:Julia has evidently joined Ilaria following the seven-month time skip at the end of season 1.]]
* AFamilyAffair: Alan became estranged from his brother Peter because the latter was having an affair with Alan's wife Julia, whom he divorced over it. When he's forced into WorkingWithTheEx and learns that Peter's life might be in jeopardy, Alan nevertheless is determined to help his brother.
* GenreShift: Around Episode 7, "Survivor Zero," the show's dramatic focus shifts from a claustrophobic ZombieApocalypse to an elaborate meta-human World Domination scheme.
* GlowingEyes[=/=]TechnicolorEyes: A defining characteristic of the Immortals is their silvery eyes. They use various methods to conceal them in order to blend in with ordinary humans. Some, like Hatake and Sutton, use contact lenses. Michael opts to have dye [[EyeScream injected directly into his corneas]]. Durant doesn't even bother, simply wearing sunglasses when she has to.
* GodzillaThreshold: When Peter's infection reaches its terminal stage, Alan insists on employing [=SODRA=] - a cure-all developed by Arctic Biosystems, even though it has [[RussianRoulette a 75% mortality rate]]. [[spoiler:Not only does it nearly kill Peter, it also fails to kill the virus.]]
* GoryDiscretionShot[=/=]ScreamDiscretionShot: {{Subverted|Trope}}. When Peter breaks into a lab full of scientists, the viewer only sees what seems to be a sudden blood spatter on the glass of the lab door, accompanied by a woman's scream. But the subsequent episode's opening scene shows no one is wounded, and reveals BadBlackBarf as the method of viral transmission.
* GrimUpNorth: Set in the blistering cold of the Arctic, in a research lab full of {{Morally Ambiguous Doctorate}}s
* HazmatSuit: Part and parcel of interacting with the infected during an outbreak. Both CDC members and Arctic Biosystems staff use them. They're referred to as Racal Suits, a kind of containment suit specifically designed for work with pathogens. {{Defied|Trope}} after the first two days, even though best practices would require continued use.
* HealingFactor: Hatake is noted to heal faster than normal. [[spoiler:He and all immortals have accelerated healing, though anything that would definitely kill a human will kill them just as easily.]]
* HeelFaceTurn: [[spoiler: Balleseros defects from Ilaria, mostly due to [[LoveRedeems Anana's influence]].]]
* HeKnowsTooMuch:
** In "Vector," Balleseros kills Dr. Graff, a ReluctantMadScientist, when he catches Graff trying to leave via snowmobile, and Graff explains that the goings-on at Arctic Biosystems must be exposed. Balleseros stabs him InTheBack.
** In "Single Strand," [[spoiler:Balleseros kills Doreen once she's uncovered the purpose of the virus and the unknown RNA contained therein. What makes it worse is that he asked her to do the research, meaning he knew he was going to kill her once she got results.]]
* HeroicSacrifice:
** [[spoiler:Daniel sacrifices his own life to let Hatake out of a SadisticChoice between sparing him or Julia, knowing Hatake could never choose him over his own flesh-and-blood daughter.]]
** [[spoiler:In the season 1 finale, when Julia is kidnapped by the Scythe with the virus and cure, Alan tries to save her. Knowing he's outmatched, she grabs the cure and kicks him out of the rising helicopter they're currently in. It takes off with her, but Alan is saved by the snow.]]
* IdiotBall: In the pilot a security guard is found dead with his hand cut off. Others wonder out loud why this is, and ''nobody'' thinks of the RFID chips all personnel have implanted there.
* ItCanThink: Despite being infected with TheVirus, the Infected "Vectors" maintain a majority of their intelligence, one shining example being an infected man using a dismembered hand to access a security door.
* ImmortalProcreationClause: Averted; immortals are capable of having children, including to each other. [[spoiler:Julia is the offspring of immortals Hiroshi Hataka and Jane Walker, although her own immortality had to be "activated" first.]]
* TheImmune: [[spoiler:The immortals are immune to all forms of disease, and as a bonus those infected with NARVIK-B actively ignore them.]]
** [[spoiler:Subverted, when we learn that the immortals are dying to the mycotic fungal plague]]
* InTheBack: In "Vector," Balleseros does this to Dr. Graff after he announces his intent to expose the research at Arctic Biosystems.
* InstrumentalThemeTune: Bossa Nova [[SoundtrackDissonance easy listening]].
* JerkassHasAPoint: In episode 5, Alan confronts Daniel over the Transgenics lab. Daniel correctly points out that he had no reason to cover up a virus he needs the CDC to cure. Secondly, he correctly questions why Alan trusts Major Balleseros more when he has known him as long as Daniel.
* KillItWithIce: Extreme cold inhibits the spread of NARVIK, though it doesn't actually kill it. The Vectors are rendered docile while exposed to extreme cold, but the temperatures required to do this are just as deadly to humans.
* KnockOutGas: In the pilot, head of security Daniel releases halothane gas into the {{Air Vent|Passageway}}s where the infected Peter is holing up, calculating a dosage that should knock Peter out for four hours. It [[SubvertedTrope doesn't affect]] Peter at all.
* LastNoteNightmare: The intro credits theme starts off as something resembling TheElevatorFromIpanema, but the last note suddenly reverses itself to indicate that something ugly is lurking beneath the surface.
* LeaveNoWitnesses: Constance makes it clear that this is the result once a cure is found. Fortunately, Alan is at least knew it's not in their best interests to let her have all the cards.
* LettingTheAirOutOfTheBand:
** The cheery InstrumentalThemeTune ends this way, warping and slowing to a stop as BadBlackBarf drips off the "X" in the TitleCard.
** The effect is {{inverted|Trope}} as its companion end credits theme begins, then played straight as it ends.
* ManiacMonkeys: Though their existence is at first denied by staff, Dr. Boyle discovers infected macaques are the source of zoonotic transfer after she's attacked by an escaped specimen. Balleseros later finds the rest of the infected lab monkeys frozen outside the base.
* MeaningfulName: The island where most of season 2 takes place shares its name with [[https://en.wikipedia.org/wiki/Count_of_St._Germain the Comte de Saint-Germain]], an 18th century courtier, charlatan and JackOfAllTrades who claimed to be over 500 years old.
* MeatMoss: In "274," adding growth factor to a petri dish of monkey blood infected with TheVirus results in an explosive growth of black biomass that coats and fills the observation chamber and threatens to shatter it until Doreen releases DeadlyGas therein. Alan and Sarah end up repeating this experiment but aren't as careful with containment, which nearly goes south until Alan turns a fire extinguisher on it. Fortunately, this teaches them that cold inhibits the virus.
* MegaCorp: Ilaria Corporation and its subsidiary Arctic Biosystems, who Doreen notes are "big pharma," and must be rich indeed to afford an arctic ElaborateUndergroundBase base that can house and employ over 120 people. [[spoiler: Justifiable, as it's run by a cabal of immortals who have been around for centuries, and as such have had plenty of time to build up resources.]]
* MercyKill: Jordan kills Dr. Van Eigem at her request with a morphine overdose, because she's [[ZombieInfectee infected with what amounts to a zombie virus]] and doesn't want to turn into one, which is deemed a {{fate worse than death}}.
* TheMole:
** Balleseros is secretly an Ilaria plant on the CDC team.
** [[spoiler:Peter is revealed to be working for Ilaria in the season 1 finale.]]
* MorallyAmbiguousDoctorate: Implicitly, every researcher at Arctic Biosystems, who come there to take advantage of the opportunity to perform research unencumbered by regulatory agencies.
* MummiesAtTheDinnerTable: In "Scion," Hatake [[spoiler: invites Julia to a family dinner featuring the putrefied corpses of his wife and adopted son Daniel. Daniel is still missing his head. And Hatake is missing a whole lot more...]]
* NoBiologicalSex: Arctic Biosystems lab rats are genetically engineered to lack sex organs, which, according to Daniel Aerov, makes them more controllable.
* NotSoDifferentRemark: In "274," when Daniel shoots one of the Vectors who's coming toward Dr. Hatake, Alan is outraged and insists that he panicked. Daniel counters that he made a judgment call and that Alan would have done the same. Alan does eventually have to turn a gun on a Vector, but Daniel is still using false equivalency; the one Daniel shot was trying to surrender, while the one Alan shot was flat-out homicidal.
* NotUsingTheZWord: The CDC refers to those who attack others to spread TheVirus as "Vectors."
* NoughtiesDramaSeries: While it started out as a straightforward thriller about stopping a plague, it quickly delved into age-old conspiracies and multi-linear plots.
* OldFlame:
** For Alan, DoubleSubverted, though initially standoffish at the prospect of WorkingWithTheEx, then outright combative as he bickers with Julia, he confesses that it's become AngerBornOfWorry, and he can't stop feeling protective of her.
** For Julia, this is {{Subverted|Trope}} with her relationship with ex-husband Alan. Though she appreciates Alan's concern, she not only doesn't reciprocate, but the sight of Peter brings back memories of her unhappy relationship with Alan, and the reasons she [[SiblingTriangle turned to Peter]] for comfort.
** However, for both Peter and Julia, this is PlayedStraight, as an infected Peter, though acting on his viral programming, first attempts a tender kiss before resorting to a DeadlyLunge, and Julia later admits to herself that she still has feelings for Peter, in spite of the fact they haven't spoken since Alan caught them cheating.
* OminousObsidianOoze: The NARVIK-B virus modifies its victims' behavior so they become super-strong, paranoid, aggressive and biologically driven to infect others via forcible transmission, which entails assaulting and restraining victims and vomiting a black secretion into their mouths. The vectors also develop TaintedVeins as their blood turns black, and adding growth factor to a petri dish of monkey blood infected with NAVIK-B results in an explosive growth of black biomass. The black gunk is such an integral visual motif that it's featured dripping off the "X" in the series Title Card.
* PatientZero: The CDC team's best guess is Peter Farragut is the first human infectee of NARVIK-B, TheVirus that turns its victims into super-strong Vectors compelled to infect others. However, the CDC is stuck with hosts who refuse to tell the whole story, and from the rantings of Vectors, other scientists likely went before him.
* PlagueZombie[=/=]TechnicallyLivingZombie: "Vectors," infectees of SyntheticPlague[=/=]TheVirus NARVIK-B, are biologically driven to infect others via forcible transmission through vomiting BadBlackBarf into their mouths. If Peter is any indication, Vectors only last a few days before the infection progresses too far for them to keep functioning. Episode 5 shows that Vectors are intelligent enough to take out lights so as to set ambushes in the darkness.
* ProfessorGuineaPig: Based on the GlowingEyes alone, Dr. [[spoiler:Hiroshi Hatake]] has been doing some interesting side research.[[spoiler: He also appears to have some sort of control over the vectors; at the very least, they show no aggression towards him and allow him to pass without attacking.]]
* ReluctantMadScientist: It's clear that some Arctic Biosystems staff are ambivalent and regretful about the work they've done, some of which may have been performed under duress.
** In the pilot, Dr. Peter Farragut makes a hand signal meant to indicate "danger" in his video logs while claiming he's excited to work at Arctic Biosystems, and "understand[s] certain things now."
** In "Vector" Dr. Tracey, infected with TheVirus, rants semi-coherently about how she should have known that genetically engineering a virus would never be used for anything good, and, alternately, that it couldn't possibly be her fault, and there was no way for her to know.
** Also, in "Vector," after witnessing [=DeKlerk=]'s capture, Dr. Graff grabs a snowmobile, and, when found by Balleseros, explains unregulated research has lost its appeal, calls it "an abomination," and expresses his intent to expose Arctic Biosystems. Balleseros stabs him InTheBack.
* ResearchInc: Arctic Biosystems is a private company staffed by over a hundred {{Morally Ambiguous Doctorate}}s who specifically come to the base, stationed in international territory, to exploit the opportunity to perform research unburdened by regulatory agencies.
* SadisticChoice: The Scythe forces Hatake to choose between [[spoiler:letting either Julia or Daniel have [[YourHeadASplode their heads blown up]], with a 30 second timer before they both go. Hatake can't bring himself to choose, so Daniel [[HeroicSacrifice sets his off deliberately]].]]
* SamePlotSequel: Season 2 changes the location from the Arctic to an island in the Pacific Northwest, but otherwise is pretty much the same as season 1: CDC officials have to contend with a viral outbreak at a remote complex with all sort of access points and secrets, and led by a mysterious leader who is actually an immortal member of a centuries-old conspiracy, with at least one member of the CDC team having unofficial ties to the conspiracy. Over the course of the season, the situation deteriorates until the number of infected reaches a critical point and the whole site has to be destroyed.
* ScienceHero: The CDC's rapid response team of pathologists and their liaison from the Army Core of Engineers have been sent to save the day in a base full of {{Morally Ambiguous Doctorate}}s.
** Dr. Alan Farragut: Head of the CDC's Special Pathogens Branch and lead of the mission
** Dr. Julia "Jules" Walker: One of the CDC's senior scientists
** Dr. Sarah Jordan: Young mentee of Dr. Farragut
** Dr. Doreen Boyle: Veterinary pathologist
** Major Sergio Balleseros: Systems Engineer
* ShoutOut:
** In the pilot, Dr. Doreen Boyle dryly notes that, given the shared tensions between divorced fellow CDC members Alan and Julia, and Alan's brother Peter, "this is gonna be the most frakked-up family reunion ever." The show is executive produced by ''Series/{{Battlestar Galactica|2003}}'''s Ronald D. Moore.
** In "Vector" Major Balleseros quotes John [=McClane=] while trailing Peter through an AirVentPassageway. Alan {{Lampshade|Hanging}}s it when he comments on how Balleseros should be too young to remember ''Film/DieHard''.
* SiblingTriangle: In the past, Julia became unhappy in her marriage to Alan and turned to his younger brother Peter for comfort. After Alan caught them in bed together, Julia divorced Alan and totally cut off contact with Peter. In the present, both brothers carry a torch for Julia, while Julia struggles with unhappy memories of her marriage to Alan and still-present feelings for Peter.
* SicklyGreenGlow: In "274" the rapid response test Sarah develops to diagnose infected patients glows green to indicate TheVirus.
* SoundtrackDissonance: Beware of easy listening music.
** The InstrumentalThemeTune is a jazzy bit of Bossa Nova that [[LettingTheAirOutOfTheBand slows and warps to a stop]] while BadBlackBarf drips off of the "X" in the TitleCard. Closed Captioning refers to it as "Happy Instrumental Music"
** In the pilot, Dionne Warwick's Baião-influenced "Do You Know the Way To San Jose" serves as musical bookends, as SourceMusic in the opening scene, Peter's introduction as an infectee as he's discovered by Dr. Hatake and his head of security, and as BackgroundMusic in the closing scene of Peter's first successful attempt to infect others as he circumvents a biometric lock to assault a lab full of screaming scientists.
** In "Vector," another bouncy easy listening tune in the same genre as the InstrumentalThemeTune serves as musical bookends, playing as SourceMusic during two frightening encounters, when Dr. Doreen Boyle is accosted by an infected Dr. Tracey, and in the closing scene when Dr. Julia Walker encounters a likewise infected Peter Farragut during decontamination.
** {{Subvert|edTrope}}ing the trend is the music played during closing credits. It begins by picking up where the "Happy" InstrumentalThemeTune left off, and has the same instrumentation, but is instead tense with a rising background whine that evokes PsychoStrings before [[LettingTheAirOutOfTheBand warping to a stop]] again.
** In "Aniqatiga", the precise, methodical, and very serious lab work that Drs. Farragut and Jordan are undertaking is accompanied by the light, airy, and fanciful Chinese Dance from Tchaikovsky's ''Nutcracker Suite''.
* StalkerWithACrush: After asking a series of increasingly personal questions in their various interactions, Dr. [[spoiler: Hiroshi Hatake]] wistfully peruses an album of pictures of Dr. [[spoiler: Julia Walker]], both posed and taken from distances suggesting covert surveillance. [[spoiler: Subverted when it turns out he's actually her father.]]
* StaticStunGun: Arctic Biosystems security techs have 600 kV stun batons, which knock humans out cold, but only irritate Vectors.
* SuperStrength: Exhibited by infected "Vectors".
** Peter Farragut can rip through restraints and 600 kV [[StaticStunGun stun batons]] don't faze him.
** Infected monkeys can rip off cage doors from the inside.
** Infected rats can barrel through glass partitions, or topple the shelves on which they're caged with little trouble.
* SyntheticPlague: It's clear that TheVirus originates from mysterious, ethically-dubious research into biological superweapons, but Arctic Biosystems' staff is willfully opaque as to the details. [[spoiler:Constance reveals that NARVIK-A is a bioweapon meant to be released into the general population, the cure to which only the Ilaria Corporation will have. NARVIK-B is an alternate strain developed by Hatake for unclear purposes.]]
* TaintedVeins: Victims of TheVirus develop black veins, particularly visible in the denuded infected lab rats the CDC researchers use for testing.
* TakeOverTheWorld: [[spoiler:Constance has this goal.]]
* TestedOnHumans: Balleseros tells Doreen that he and his superiors suspect the outbreak may have begun as a deliberate effort to test a SyntheticPlague on human subjects that got out of control.
* ThereWasADoor: In "Vector," an infected rat breaks through the glass walls of its own cage and that of an uninfected potential victim, even though its SuperStrength could've surely dislodged its cage's lid quite easily.
* TheyCallHimSword: The Scythe is an assassin named after his weapon, to the point that he [[DoNotCallMePaul hates being called by his real name]].
* TimeSkip: The season 1 finale jumps ahead to Day 235 for one scene, goes back to the present to round off events at Arctic Biosystems, then goes back to 235 to set up the next season.
** Season 2 does one better, running two concurrent timelines: [[spoiler: one 15 months after the event of Season 1, at the start of a new epidemic, and one thirty years after that, at the end of it.]]
* TitleCard: White brickwork with black lettering. BadBlackBarf drips off the "X" as the InstrumentalThemeTune ends.
* TitleIn: Usually denotes timeline: "Day 1, Day 2," etc. in black font on a white background, though text also introduces an EstablishingShot of the CDC HQ.
* TrashTheSet: In the season 1 finale, [[spoiler: The Scythe blows up Arctic Biosystems, leveling the whole facility]].
* TruthInTelevision:
** Both NARVIK strains were recovered from the depths of the Antarctic ice pack. The CDC scientists are bewildered by ancient viruses being resurrected... which is also [[http://www.bbc.com/news/science-environment-26387276 feared in real life.]]
** How dark the pigmentation is in the iris of the eye does affect how sensitive the eye is to the light. People with pale blue eyes are (slightly) more sensitive to bright light than those with dark brown eyes, for example. This is also why people with albinism have eyes that are very sensitive to light, as they lack pigmentation in the irises.
* VasquezAlwaysDies: An ActionSurvivor example, given the setting. [[spoiler:Doreen is a no-nonsense scientist who rolls with everything thrown at her, in contrast to the more feminine, and more frequently victimized Julia and Sarah. Doreen dies in "Single Strand," the fourth episode.]]
* VeinOVision: In "Bloodline", we see some people through the eyes of a vector that's crawling through a dining-area ceiling duct, and a network of vessels shines pale green inside each person.
* TheVirus: Unlike NARVIK-A, which causes hemorrhagic shock and eventually liquefies its victims, NARVIK-B, the mutated strain Peter Farragut carries, does not kill its victims, but instead modifies their behavior so they become super-strong, paranoid, aggressive and biologically driven to infect others via forcible transmission, which entails assaulting and restraining victims and [[BadBlackBarf vomiting a black secretion]] into their mouths.
* WeAreEverywhere: The [[spoiler: immortal]] Ilaria member whom Alan is torturing in the season 1 finale time skip claims that "Ilaria is everywhere".
* WhatHappenedToTheMouse: Of the six staff members Peter attacks after he bypasses a biometric lock, we only see five in-series, though six are named. In a video on the [[http://www.syfy.com/accessgranted/helix Access Granted]] website, we see the sixth, Dr. Raver, dressed in parka with name tag, walking along a cliff side, then collapsing while BadBlackBarf drips from his mouth, all while Hatake's voice recites from ''Theatre/{{Hamlet}}'' in Japanese.
* WorkingWithTheEx: Dr. Alan Farragut must work alongside his CDC peer and ex-wife Dr. Julia "Jules" Walker, who, in spite of their interpersonal tensions, has recommended him to head the mission as a personal favor due to the fact his brother Peter is among the infected.
* ZombieInfectee: PlayedWith in many ways.
** In "274" {{Zigzagged|Trope}} when Julia goes into denial after her infection by Peter. When Alan finds her in the shower, she claims she passed out from fatigue, and tries to psych herself up, insisting "You. Don't. Get. Sick." A test initially and inexplicably clears her of infection, while she begins to project, accusing Sarah of being infected. But when Julia witnesses a Vector attack a security tech and coughs, she {{Subvert|ed Trope}}s it, showing her mucus covered hand and insisting she be quarantined. Later she realizes her swab still reads clear, so the rapid response test used to diagnose her and dozens of others ''doesn't even work.''
** Also in "274," the trope is {{Exaggerated|Trope}} when an escaped Dr. Bryce is discovered attacking a lab door with an ax while ''demanding a cure'', and upon confrontation, ''still'' [[ImplausibleDeniability insists]] he isn't infected.
-->'''Dr. Bryce''': "I'm not even infected!" *swings ax, coughs BadBlackBarf* "Or at least I wasn't until you threw me in with the rest of 'em!"
** Then, {{Inverted| Trope}} in "274," when Julia's psychological projection causes her to accuse coworker Sarah. Though Sarah exhibits a prominent hand tremor, that symptom is from another medical condition Sarah is keeping secret.
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