Literature / Sigma Force

Sigma Force is a techno-thriller series by author James Rollins (a pen name for Czech-American Jim Czajkowski) chronicling the exploits of a covert special forces agency, recruited by the Defense Advanced Research Projects Agency (DARPA) for their incredible intelligence as well as fighting skills. Together the team goes on missions to investigate and secure discoveries, both technological and historical, that could hurt the United States and the world, which more often that not brings them to a clash with the Guild, a mysterious organization bent on world domination.

Main Books

• Sandstorm (2004) — In many ways a prequel novel, Sandstorm follows Painter Crowe, future head of Sigma Force, on the mission that led up to his promotion. After an explosion at the British Muesum, Painter teams up with the wealthy Lady Kara Kensington and her foster sister Safia Al-Maaz to find the lost city of Ubar in Oman and the lake of antimatter it rests on. They are pursued by former Sigma agent, Cassandra Sanchez, who works for the mysterious Guild.
• Map of Bones (2005) — The first book to introduce the series protagonists — Gray Pierce, Monk Kokkalis, and Kat Bryant. After the massacre of an entire congregation attending mass in Cologne Cathedral in Germany, during which its most prized treasure — the bones of the Three Magi — were stolen, Sigma joins up with Rachel Verona, a beautiful Italian archaeologist, and her uncle Vigor, a priest and custodian of the Vatican Archives, to find the bones and discover a mysterious substance that may have been the source of Biblical miracles while clashing with the Dragon Court and its enforcer, Raoul de Sauvage. The series also introduced Seichan, an agent of the Guild with unclear allegiances. The book also features a rare benevolent Vatican secret society.
• Black Order (2006) — While Gray goes to Denmark to find Charles Darwin's family Bible, Painter heads to Tibet where he finds a Buddhist monastery full of dead monks and a swastika painted in blood. Both their teams find themselves in a battle between two groups of Those Wacky Nazis intent on uncovering research on creating Super Soldiers, delving into Nazi Germany's real-life genetic and nuclear experiments.
• The Judas Strain (2007) — Gray teams up once again with Seichan and Vigor to seek out the key to stopping a strange disease that has broken out aboard a cruise ship off the coast of Indonesia (where Monk is representing Sigma in the relief/investigation efforts) that threatens the entire world. The series also introduces Joe Kowalski, a hulking ex-Navy soldier. The first book in the series to have a Twist Ending, meaning most plot threads from future books will invariably spoil the previous highly serialized installments.
• The Last Oracle (2008) — A cabal of disgruntled ex-Soviet officials has been bioengineering autistic Roma children into becoming psychic prophets... while hatching a plan to massacre world leaders convening at Chernobyl to witness the sealing of its contaminated reactor, leaving Russia the sole superpower. Painter would have to deal with one such child who somehow made it to America, Gray and Kowalski travel to Chernobyl to stop said cabal, and Monk has to accompany a group of such children to the area around the highly radioactive Lake Karachay.
• The Doomsday Key (2009) — Three murders separated by distance (the Vatican, Mali and Princeton) are connected by the victims sharing the same Celtic cross seared onto their chests. Meanwhile, a Norwegian corporation is making questionable genetically modified crops. Gray, Kowalski, Rachel and Seichan travel across Britain to find connections between said company's crops and 800-year-old cases of "death with a full stomach", while Painter, Monk and newcomer John Creed travel to Norway to investigate the company itself.
• The Devil Colony (2011) — A cataclysmic explosion in Utah portends an even greater catastrophe: the long-overdue eruption of the Yellowstone supervolcano. Blame for the blast is pinned on a radical Native American youth organization protesting the "desecration" of a sacred graveyard by an archaeological team — among whose ranks is Painter's niece, Kai Quacheets. Gray and Kowalski must infiltrate Fort Knox to uncover secrets related to the blast, Kai must fight for her life and prove her innocence, a Japanese research team affiliated with Sigma is on the lookout for strange stirrings in Europe, and Painter discovers a truly horrifying secret — one which extends all the way back to the origins of the Mormons and the founding of America.
• Bloodline (2012) — Somali pirates kidnap Amanda Gant-Bennett, the pregnant, runaway daughter of President James Gant. Gray and Seichan set out to rescue her and her unborn child, accompanied by Army Ranger Tucker Wayne and his combat dog Kane, Kat and Lisa get in on the action by investigating rumors about a fertility clinic in Charleston, South Carolina, and Painter, Monk and Kowalski investigate links between Amanda's kidnapping, the Guild, and a staff said to have been used by Jesus himself — reputed to hold the key to immortality.
• The Eye of God (2013) — An American satellite used to conduct research on the dark energy contained in a comet crashes somewhere in Mongolia, setting off a wild scramble to find it, but not before relaying a horrifying image of the Atlantic coast of America in ruins. Meanwhile, Vigor Verona receives a mysterious package from a colleague who supposedly disappeared a decade ago — a skull etched with Aramaic writing and a book bound in human skin, both of which are identified to be Genghis Khan's. Sensing something is afoot, Gray and Sigma reunite with the Veronas to investigate links between the crashed satellite, relics of the Khan, the fall of the Roman Empire, and rumors of an ancient superweapon — while forcing them to question the very nature of reality itself.
• The Sixth Extinction (2014) — A military research station in Utah suddenly experienced a blight, killing any living thing within 50 square miles. To keep it from spreading, Gray and Sigma travel the world in search of clues, leading them to a map salvaged from the Library of Alexandria and clues of a time when Antarctica was not the frozen wasteland it is today.
• The Bone Labyrinth (2015) — Two near-simultaneous attacks — one, at an underground chapel in Croatia holding the bones of a Neanderthal woman, the other at a primate research facility near Atlanta — trigger Sigma's latest journey of discovery, one that will take them through 50,000 years of human history and across South America, leading not only to a Neanderthal graveyard, but also what could be their greatest challenge yet: an ancient force revived by 21st-century genetics which may either bring about the evolution or eradication of humanity.
• The Seventh Plague (2016) — When an old colleague of Safia suddenly turns up dying, two years after supposedly disappearing in the deserts of Sudan, coroners were astounded to discover that he was apparently mummified while still alive. When the same team contracts a fatal disease that rapidly spread all over Cairo, however, Safia turns to her old friends at Sigma. Painter heads to disease-stricken Cairo, while Gray and Seichan investigate a Mad Scientist holed up in the Arctic, both of their travels bound by the mystery of Mark Twain's travels, the wisdom of Nikola Tesla, the truths behind the expedition to find David Livingstone in Africa, and said professor's own research which may prove the historical plausibility of the Ten Plagues of The Bible.
• The Demon Crown (2017) — The massacre of a scientific team investigating a recently-ravaged island off the coast of Brazil somehow links back to a cache of bones preserved in amber and stashed away at the Smithsonian Institution, said to carry both the promise of immortality but also the threat of the eradication of humanity. When that power inexplicably breaks free, however, Sigma Force sets off to stop this threat. But when the new threat proves as dangerous as it is cunning, Sigma may have no choice but join forces with an old enemy if humanity is to be saved.
• Crucible (2019) — Grayson Pierce and Sigma as a whole are caught on the wrong foot when he comes home to find his girlfriend Seichan as well as his best friend Monks daughters missing and Monk's wife Kat badly injured. As he tries to find out what happened, he gets thrown into a huge complicated mystery involving witches and A.I.s...
• The Last Odyssey (2020) — In the frozen tundra of Greenland, a group of modern-day researchers stumble upon a medieval ship buried a half-mile below the ice. The ship's hold contains a collection of artifacts dating back to the Bronze Age. Inside the captain's cabin is found a clockwork gold map embedded with an intricate silver astrolabe. Once activated, the moving map traces the path of Odysseus's famous ship as it sailed away from Troy. But the route detours as the map opens to reveal a fiery river leading to a hidden realm underneath the Mediterranean Sea, the subterranean world of Tartarus. When word of Tartarus spreads, and of the cache of miraculous weapons said to be hidden there, tensions explode in this volatile region. Sigma Force must now go where humans fear to tread. To prevent a tyrant from igniting a global war, they must cross the very gates of Hell.
• Kingdom of Bones (2022) — A United Nations relief team in a small village in the Congo makes an alarming discovery. An unknown force is leveling the evolutionary playing field. Men, women, and children have been reduced to a dull, catatonic state. The environment surrounding them—plants and animals—has grown more cunning and predatory, evolving at an exponential pace. The insidious phenomenon is spreading from a cursed site in the jungle — known to locals as the Kingdom of Bones — and sweeping across Africa, threatening the rest of the world. To head off global catastrophe, Sigma Force must risk their lives to uncover the shattering secret at the heart of the African continent—a truth that will illuminate who we are as a species and where we may be headed . . . sooner than we know. Mother Nature—red in tooth and claw—is turning against humankind, propelling the entire world into the Kingdom of Bones.

Tucker and Kane Books (with Grant Blackwood)

• The Kill Switch (2014) — A simple mission to rescue a Russian pharmaceuticals magnate with knowledge to a bio-weapon becomes complicated when Painter contacts Tucker, desperately urging him to find Mad Scientist Abram Bukolov before a shady general, who's also after everything he knew about a dangerous superweapon from the recent past, does.
• War Hawk (2016)

Short Stories

• The Skeleton Key (2010) — Seichan awakes with a metal collar rigged with explosives around her neck and a strange boy by her side. Forced to fight for her life, she and the boy race through the streets of Paris and beneath to stop an apocalyptic cult.
• Tracker (2012) — Before they met Sigma Force, Tucker and Kane rescue a woman fleeing three assassins on the streets of Budapest, only to realize that she holds the key to a terrible secret originating from Nazi Germany's final days.
• The Midnight Watch (2015) — What started as a hack into the servers of the Smithsonian Institution begins to escalate as a series of increasingly violent ones. Sigma's muscle, Joe Kowalski, is sent in to save a scientist trapped in the National Museum of Natural History, even as he is led into a wild chase that may lead him to the secrets of the National Zoo.
• Crash & Burn (2016) — Seichan and Kowalski have to set aside their differences in order to survive the night at a volcanic island, even as they run into what looks like a superweapon.
• Ghost Ship (2017) — Gray and Seichan's beach vacation in Australia is ruined by the discovery of a burned body. Before they become the next victims, they take matters into their hands, all the while uncovering the truth behind the disappearance of a convict ship at the Great Barrier Reef during the early days of British colonization of Australia.

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Sigma Force contains examples of:

• Adventurer Archaeologist: Safia al-Maaz and her ex-fiance and later husband Omaha Dunn. A character lampshades it in the Omaha's case, calling him Indiana Jones. Omaha's brother Danny is a downplayed example.
• A.I. Is a Crapshoot / Benevolent A.I.: The two versions of Eve in Crucible.
• Ancient Astronauts: Implied with the big discoveries of many of the books, but perhaps the biggest one is the nano-enhanced gold artifacts featured in The Devil Colony.
• Atlantis: One of the revelations in The Bone Labyrinth is that Atlantis is actually South America.
• Artificial Limbs Are Stronger: After getting his hand lopped off, Monk gets a prosthetic hand that's strong enough to let him hold on to a plane and can be remotely operated.
• Artistic License: Of a variety of types. One of the biggest ones (acknowledged by Word of God) is that the Dragon Court (the overt Nebulous Evil Organization from Map of Bones) is a real group, but they are actually very benevolent and philanthropic, not the world domination seekers depicted in the novel.
• Badass Bookworm: Sigma Force members are recruited based on both their military and intellectual prowess. Once drafted from the military, recruits are given crash courses on their chosen fields of study.
• Battle Couple: Gray and Seichan, once she gets out of her Heel–Face Revolving Door.
• Beethoven Was an Alien Spy: Historical figures have figured into the stories of several novels in this series, such as Marco Polo, the Oracle of Delphi, Thomas Jefferson and Genghis Khan.
• Big Bad
  • Sandstorm: Cassandra Sanchez and her superior, Sigma Director Tony Rector
  • Map of Bones: Raoul de Sauvage, Imperator of the Dragon Court. It's actually General Rende
  • Black Order: Sir Baldric Waalenberg, with his many children as a collective of dragons
  • The Judas Strain: Two Guild operatives — Amen Nasser (Gray, Pete, Seichan and Vigor) and Devesh Patanjali (Monk, Lisa and the passengers of the Mistress of the Seas)
  • The Last Oracle: General-Major Savina Martov
  • The Doomsday Key: Krista Magnussen and Wallace Boyle, member of "Echelon", a higher-up of the Guild
  • The Devil Colony: Rafael Saint Germaine
  • Bloodline: First Lady Teresa Melody Gant
  • The Eye of God: Batukhan
  • The Sixth Extinction: Cutter Elwes
  • The Bone Labyrinth: Jiaying Lau
  • The Seventh Plague: Simon Hartnell
• Bilingual Bonus: Although most foreign phrases are translated for the readers' convenience, some are left up to the reader to figure out, such as "svoloch", a Russian word for "scum", featured in The Last Oracle.
• Bizarre Alien Biology: In The Sixth Extinction, an entire ecosystem is found underneath Queen Maude Land in Antarctica, filled with utterly alien species, including an eel that has an anglerfish lure which is coated in corrosive acid and a parasitic larval stage.
• Black-and-Gray Morality: The two groups of "former Nazis" featured in Black Order.
  Painter Crowe: We're not dealing with a new enemy here... We're dealing with the same one. More Nazis.
• The Bus Came Back:
  • Danny, Lisa's mountaineering brother, re-appears in The Sixth Extinction only to fall victim to the plague sweeping the area and having to have his leg amputated.
  • Safia al-Maaz reappears in The Seventh Plague, after being absent since Sandstorm.
• Canis Latinicus: In Map of Bones, whenever the Three Magi are discussed, they're always referred to in the plural form, even when talking about a particular one, such as the hypothetical Fourth Magi, despite the fact that the proper singular form is "Magus".
• Chickification: Kat Bryant, sadly. After being introduced in Map of Bones as a Badass knife wielder with a penchant for slitting throats with aplomb, she is quickly thrown in a relationship with Monk, knocked up, slapped with a desk job and left Out of Focus for many of the following books, to the point that Painter, the aging director of Sigma, sees more field time than she does. Subverted come Bloodline, fortunately, where she and Lisa get to join in on the action by investigating a fertility clinic in Charleston before being tasked with securing William, Amanda's genetically-altered newborn son.
• Chuck Cunningham Syndrome: Fiona, and both Veronas as of The Devil Colony.
• Continuity Nod:
  • Kowalski makes a couple of references to their experiences in Ice Hunt when he's tagging along with Grey in The Judas Strain.
  • The entire plot of The Judas Strain occurs as a result of a Guild operative recovering a document from the Dragon Court's headquarters in Map of Bones. Seichan even uses the Dragon Court's seal to alert Vigor to the fact that something's about to go down.
• Creepy Child: The four Gypsy children from The Last Oracle: Konstantin, Pyotr, Kiska, and Sasha. Justified because they are autistic and the product of psychic experimentation.
• Darkest Hour: The middle of Bloodline, when President Gant orders Sigma shut down after his daughter Amanda was apparently killed during her rescue attempt. Fortunately Painter turns the situation around when not only does Tucker bring the real Amanda, alive and well, but also convinces the President that someone in his own family may have staged her "death".
• Deadpan Snarker: Monk and Kowalski.
• The Dog Was the Mastermind: Who knew the seemingly sweet, loving First Lady, Teresa Melody Gant, is the one responsible for all that has happened from Sandstorm to Bloodline?
  Kowalski: Fuck me.
• Double Reverse Quadruple Agent: Seichan was a mole in the Guild all along, as revealed at the end of The Judas Strain. Her Establishing Character Moment— trying to release an anthrax bomb over Fort Detrick— was a ruse to get the Guild to trust her; the bomb had secretly been sterilized.
• Early-Installment Weirdness: Sandstorm very much different from later books in the series, in that only Painter is shown from Sigma (besides Cassandra). Afterwards, he is promoted into a cushy desk job, and more Sigma operatives are brought in as main characters.
• Earn Your Happy Ending: Many of the novels have this for the Sigma team, but the biggest example is Bloodline.
• Enforced Method Acting: In-Universe in two cases:
  • Black Order: After Fiona got shot in the middle of a crowded amusement park, Gray scoops her up and tells her to play up her pain by screaming while he starts yelling "BOMB!" at the top of his lungs.
  • The Judas Strain: To create a distraction, Gray jumps off a scaffold on the Hagia Sophia. He actually does hurt his ankle in the fall, prompting the museum director to call an ambulance.
• Even Evil Has Standards: Seichan is disgusted by an associate of the Dragon Court in Map of Bones, a corrupt Vatican priest who prefers youn girls "for sport".
• Everything Explodes Ending: Happens all too often in the books, often at the expense of the destruction of one or more valuable pieces of history, including Ubar in Sandstorm, Atlantis in The Bone Labyrinth, and Simon Hartnell's Wardencylff Tower replica in The Seventh Plague. A chapter-ending one occurs when Raoul firebombs the tomb of Alexander the Great in Map of Bones.
• Evil Plan: Many of the books involve Sigma trying to stop the Big Bad from precipitating a possible disaster that could lead to a Class 5-6 catastrophe.
  • Sandstorm: Antimatter destruction, precipitated by a sandstorm currently ravaging Oman.
  • Map of Bones: Discovering and exploiting the secret library of the Magi to allow the Dragon Court to rule the world.
  • Black Order: Quantum devolution of all living things.
  • The Judas Strain: Exploiting a bacteriophage that mutates benign bacteria into deadlier versions of themselves, and exploiting a survivor in order to develop a cure for it.
  • The Last Oracle: The radioactive waters of Lake Karachay being unleashed to the world.
  • The Doomsday Key: A fungal mutation attached to genetically modified corn.
  • The Devil Colony: Nanites eating the landscape and essentially wiping out vast pockets of land.
  • Bloodline: The eponymous Bloodline, an even more mysterious group than the Guild, attaining immortality and the power to have their way with the world.
  • Unusually there really isn't one in Eye of God (the end of the world the protagonists need to avert comes from an asteroid).
  • The Sixth Extinction features an indestructible virus tailored to reduce humans to the intelligence of animals.
  • The Bone Labyrinth: the Chinese government attempting to engineer a hybrid race of supersoldiers using Meganthropus (giant hominid) and Gorilla DNA.
  • The Seventh Plague: Giving the world free energy; see Well-Intentioned Extremist.
• Expy: Gregory Metcalfe, (The new DARPA Director since The Doomsday Key) seems like one of Leon Vance.
• Genetic Engineering Is the New Nuke: Factors into a few books.
  • In The Sixth Extinction, the Big Bad is attempting to engineer an indestructible virus using a viral shell developed by the US Government, which requires DNA from a species in an Antarctic "Shadow Biosphere".
  • In The Bone Labyrinth, the Evil Plan involves trying to genetically engineer supersoldiers using the DNA of an extinct, giant hominid and gorillas.
• Guile Hero: Painter, more so in Bloodline when he decides to keep silent about his suspicions about the Gants even to Gray. The latter, initially confused, ultimately understood that with so influential a family they can't afford to blow their cover.
• Half-Human Hybrid: Factors into the plot of the Bone Labyrinth in several ways: the plot-driving MacGuffin is a skeleton of a first-generation Homo sapiens-neanderthal hybrid, the half-neanderthal gorilla Baako, and the half-gorilla half-meganthropus engineered by the Big Bad.
• Halfway Plot Switch: The Bone Labyrinth starts with the theft of the skeleton Human-Neanderthal Hybrid and an attack on an excavation team, and ends up with half of Sigma Force finding and then destroying Atlantis.
• Heel–Face Revolving Door: Seichan seems to switch allegiances with reckless abandon until around The Devil Colony, by which point she has defected to Sigma for good.
• Heel Realization
  • Map of Bones: Raoul had this moment after his exposure to the blinding light of the Magi's labyrinth, where he is left a paralyzed, mumbling mess apologizing for his atrocities before Seichan shoots him out of his misery.
  • Bloodline: By the time Gray met him, Robert Lee Gant, the man behind the Guild, is already beginning to show genuine remorse over the atrocities he has done, such as ordering the bombing at Gray's house that killed his mother Harriet — all because he cannot turn his back on the Deal with the Devil he had made with the Bloodline when he was very young and very naive.
• Heroic Bastard: Seichan is the product of Robert Gant's dalliance with an Asian woman (later revealed in Eye of God to be Triad boss Guan Yin), making her a highly-sought prize by the Bloodline, which have been manipulating Robert's ambitions for presidency, forcing Robert to recruit Seichan as an agent, Hidden in Plain Sight from the Bloodline's prying eyes.
• Hoist by His Own Petard: Cutter Elwes, in The Sixth Extinction, is injected with the same prion he developed, which ends up destroying his higher cognitive functions.
• Hollywood Autism: Several autistic children figure into the plot of The Last Oracle, and they're not portrayed in a terribly realistic manner.
• Honorable Elephant: In The Seventh Plague, the elephants in Akagera Naitonal Park treat Jane, Monk and Gray with hospitality, and give them the key to curing the archea infection.
• Honorary Uncle: Seichan is referred to as "Auntie Seichan" by Monk and Kat's daughters in Crucible, especially by little Harriet
• I Gave My Word: In Bloodline, President Gant promised to Painter that he will wreak punishment on whoever abducted Amanda. And he truly is a man of his word — by keeping the mastermind, his own wife Teresa, a conscious vegetable through the same life-extension technology she helped create.

• Killed Off for Real
  • Black Order: Logan Gregory, Deputy Director of Sigma Force
  • The Last Oracle: Sean McKnight, Director of DARPA
  • The Doomsday Key: John Creed, new Sigma Force agent
  • The Devil Colony: Harriet Pierce, Gray's mother
  • Bloodline: Robert Lee Gant, Seichan's father, older brother of President James Gant, secretary of state, and the Guild's highest-ranked pawn; also doubles as Redemption Equals Death
  • Eye of God: Rachel Verona, archaeologist, and her uncle Vigor, curator of the Vatican Library (though The Stinger implies that they live on in a parallel universe)
  • The Seventh Plague: Jack Pierce, Gray's father and retired soldier, euthanized by his own son due to advanced Alzheimer's disease.
• Kissing Cousins: In Map of Bones, Rachel's nonna tells her that she was forced to carry two children fathered by the Baron de Sauvage (grandfather of Raoul, The Dragon of the story.) This means that Rachel is expected to marry her step-second-cousin.
• Mad Lib Thriller Title: The Judas Strain, The Doomsday Key, The Devil Colony.
• Maybe Magic, Maybe Mundane: Crops up at least Once an Episode by Black Order.
  • In Map of Bones, the Magi's archive completely vanishes in a flash of blinding, seemingly holy light. Is it a result of the monatomic gold superconductor being Applied Phlebotinum to the point where teleportation or dimensional shifting is possible, as Kat has suggested throughout the book? Or did some kind of divine intervention actually take place?
  • In Black Order, is Die Glocke really capable of bending reality based on belief?
  • In The Judas Strain, the team encounters angelic script in Angkor Wat, despite the fact that the language was said to have been fabricated centuries after the temple was built. Combined with the fact that Susan Tunis finds a group of angel-like beings after the fact, and the fact that she seems to be living in a dream world after she does so, the book points to there being something magical about the script, even if it's not outright angelic.
  • In The Bone Labyrinth, Atlantis has a sculpture with a view of the moon's dark side, something which would have been impossible for those who had been in the city to see in ancient times. One of the theories presented in the book is that the inhabitants of Atlantis were Biblical Watchers, a form of angel; whether they're actually this, or some form of Ancient Astronauts, is never explained.
• The Man Behind the Man: The Guild's (or rather, the Bloodline's) principal modus operandi is manipulating any ambitious people into unwittingly giving them what they wanted through sleeper agents before making off.
  • The Doomsday Key: Krista was sent to seduce the head of Viatus Corporation, a Norwegian GM food company, into giving her (and the Guild) the mutant fungi which can instantly kill people who eat food infected with them as well as the antidote, with which they can control human population as they will. Once they're done, they can dispose of Viatus and pin the blame on the plague they are about to unleash on the disgraced company before making off.
  • Bloodline: The eponymous Bloodline, a race of world-domination seekers who, tired with the Guild's repeated failures, decide to personally go into action by seeking immortality, manipulating the Guild's scientists into experimenting with women who can carry children with triple-helix DNA before assassinating both President James Gant, who is married to one of their own — Teresa — as well as as his brother, State secretary Robert Lee Gant, allowing Teresa to exploit national mourning and sympathy into becoming the President and thus the Bloodline's external arm.
• The Mole:
  • Featured in Sandstorm. It's Tony Rector, director of Sigma at the time, who's replaced afterwards by Painter after the former chose to shoot himself rather than face trial.
  • Crops up again in The Judas Strain. Seichan reveals herself to be a mole within the Guild.
• Obfuscating Disability: In order to get the drop on the Guild agents holding him and his wife hostage in The Judas Strain, Jack, a retired soldier with Alzheimer's, starts acting extremely agitated, as if his dementia is getting worse. But he's faking it — he's still fully in control of his mental faculties, so he and Harriet work together to escape. The fact that he's an amputee helps the Guild underestimate him further.
• Our Angels Are Different: There's debate as to whether or not they exist, but an Angelic language pops up as a major plot point in The Judas Strain, and is discovered underneath Angkor Wat, where it has no right to be, apparently making up the shape of a double helix of DNA. In The Stinger, Susan Tunis, the Living Macguffin of a large part of the story, finds herself in a cavern in Cambodia surrounded by beings resembling fluorescent nervous systems, described by her as 'Angels in the Dark'.
• Papa Wolf: A principal theme in Bloodline. President Gant is apparently very concerned for Amanda, to the point that he swears to Painter that he will turn the lives of whoever kidnapped Amanda into a "living hell". Likewise, Robert is this to Seichan, shielding him from the bullets of Bloodline agent Petra.
• Past-Life Memories: Shows up in The Seventh Plague. The arcahea microbe's ability to live off of electricity allows them to absorb electrical impulses from the brain— particularly memories— and transfer them. Those who are infected (or take the cure, as Mark Twain notes towards the end of the book) see the memories of others affected by the microbes; when Safia gets infected, her visions of the past are presented as a Present Tense Narrative.
• Playing Possum: Bloodline's climax is the staged "assassination" of President Gant, who already knew that someone in his own family may be responsible for Amanda's kidnapping, with Gray as the "killer" sniper and Tucker detonating small explosives meant to make the President bleed as part of the ruse. After that, Sigma would only have six hours to uncover the source of their troubles before the President is to be stated to have "miraculously survived" the attempt.
• Poirot Speak: Averted. Most foreign dialogue from foreign characters consists of either muttering (Ryan's father in Black Order), giving orders (Baldric and his children, again in Black Order), and/or swearing (Nicholas in The Last Oracle is particularly fond of yelling "svoloch").
• Pregnant Badass: Seichan in "The Demon Crown" and "Crucible".
• Rape Is a Special Kind of Evil: Raoul de Sauvage in Map of Bones, wants to perform their own 'cavity search' on Rachel.
• Red Herring Twist: The Devil Colony ends with Painter coming to the conclusion that President James Gant may have had a hand in the Guild's operations, and Bloodline apparently begins with a fast-forward to Gray, who has more than enough reason to be angry following his mother's death in a bombing meant for him, apparently about to snipe the President. Except the "assassination" was actually a ruse (with Gant himself as a willing participant) meant to distract the Guild while Sigma roots out its higherups — among which is President Gant's own wife, Teresa, a member of the eponymous matrilineal clan desirous of world domination.
• Redemption Equals Death: In Bloodline Robert Lee Gant, older brother of President James, is outed as the apparent leader of the Guild. By the time Gray met him, however, he is already showing genuine remorse over his past actions (such as indirectly killing Gray's mother). So he finally decides to do the right thing — by shielding his daughter Seichan from Bloodline assassin Petra. Quote his final words...
  Robert: No father should lose a daughter...
• Right-Hand Attack Dog: Kane, Tucker's dog. Unlike most examples, however, Tucker treats Kane with respect and care, and even had literal Pet the Dog moments with him (such as comforting him after he had to kill what he thought to be a dog (actually a robotic drone)).
• Scenery Porn: Occasionally, but most prevalent in Black Order, where Rollins describes in great detail the decor of the meeting hall in Copenhagen where the auction is being held... except he actually uses it as an opportunity to criticize Scandinavian design (which he calls a "total lack thereof").
• Screw the Rules, I'm Doing What's Right!: Gray used to be an Army Ranger, but when his superior made a bad decision with an unnecessary human cost, he was so enraged that he struck the man, earning himself a court-martial and a sentence in Leavenworth, during which time he studied philosophy and religion and was afterwards recruited by Sigma.
• Shock and Awe: From beginning to end, Map of Bones is all over this trope. Sandstorm too, and also Black Order, but to a much lesser extent.
• Sir Swears-a-Lot: Fiona. Mostly in British English, but American readers should get the gist.
• Suspiciously Similar Substitute: Kowalski, introduced in The Judas Strain, is basically Monk in the body of Jack Reacher.
  • Rafael Saint Germaine, Big Bad of The Devil Colony, to Raoul de Sauvage of Map of Bones being both French Jerks with a savage taste for bloodshed, though Raphael lacks Raoul's predilection for rape and leans on being more of a Noble Demon.
• The Stinger/Twist Ending: Starting The Judas Strain onwards, the novels end with a tantalizing preview of the next one.
  • The Judas Strain: An SOS signal from Monk, who apparently drowned while on a rescue mission off the coast of Indonesia.
  • The Last Oracle: A drawing of Seichan's dragon pendant, shown by one of the recuperating autistic savants to Gray.
  • The Doomsday Key: A tattoo of a divider, a crescent and a star on Wallace's back, which is a portent to Painter.
  • The Devil Colony: Doubles as a Sudden Downer Ending — Gray's mother, Harriet, is killed in an explosion at their house meant for him, while Painter comes to the conclusion that President Gant may have had a hand in the Guild's operations.
  • Bloodline: Robert Gant's dying words to his daughter Seichan that her mother is still alive, and a poem about how the Bloodline, which manipulated the Gants from the shadows and thus the power behind the Guild's operations, may rise once more to haunt Sigma Force.
  • Eye of God: Rachel, who was killed in action, and Vigor, who apparently committed suicide to be together with her, apparently living anew in a parallel universe where both came out of their ordeal unharmed.
  • The Sixth Extinction: Regretting his previous decision to throw away a miracle cure for his father, Gray uses a second one (this one designed by the Big Bad as a cure for his Evil Plan) to (possibly) cure his father's alzheimers.
    • And then another one immediately after in which it's revealed that Cutter Elwes' bioengineered giant sloths escaped his countermeasure.
  • The Seventh Plague has Gray euthanizing his father Jack via morphine overdose, as his condition has deteriorated despite the aforementioned cure, while Seichan has a premonition that the Guild may be resurgent after being apparently eradicated at the end of Bloodline with the death of her father Robert Gant.
• Theme Naming: All of the animals in the 'shadow biosphere' in The Sixth Extinction have an X in their scientific name to emphasize the xenobiological nature of everything down there.
• The 'Verse: In addition to the Sigma Force books, Rollins has also written 6 stand-alone novels on his own over the course of his career. Three of them (Subterranean, Deep Fathom, and Ice Hunt) exist in the same universe and continuity as the Sigma series. Lisa Cummings was originally a supporting character in Deep Fathom, while Joe Kowalski appeared in Ice Hunt, which incidentally were already linked due to the appearance and mention of a minor character in both books. Most recently, Tucker Wayne starred in The Kill Switch in a spin-off that Rollins co-wrote with Grant Blackwood, while Jason Carter, having previously appeared as 10 year old kid in Rollins' first book Subterranean, is now Sigma's newest recruit as of The 6th Extinction.
• "Well Done, Son" Guy: Gray's father, Jack, who has Alzheimer's (thus bordering on Deconstruction territory).
• Well-Intentioned Extremist: Simon Hartnell; he wants to provide free energy to the world, following in the footsteps of his idol Nikola Tesla. Unfortunately, his plan includes at least three different ways in which he can end the world: firstly, his power source is an electricity-breathing microbe that was the root cause for most of the Ten Plagues of Egypt, which breaks loose in modern times, and is often lethal. Those it doesn't kill are left as bearers of a potential Sterility Plague which could result in the extinction of humanity. On top of that, the energy output created by wireless energy generator has the potential to ignite the ionosphere.
• Shout-Out: The series got one from Steve Berry in 2007, in The Venetian Betrayal. Later, the paperback re-release of The Last Oracle included a teaser chapter of Berry's 2009 novel The Paris Vendetta.