The Core Four — Mariner, Boimler, Tendi and Rutherford — are assigned to the same mission for the first time all season. However, Mariner is frustrated to learn that the mission involves investigating a cave, in which they (inevitably) get trapped and have to figure their way out. However, the plot focuses less on their technobabble and more on the fact that the four characters have been going their separate ways and their friendship is becoming strained.
Tropes:
- A Day in the Limelight:
- T'Ana gets to be the co-lead in Rutherford's segment, in her first substantial appearance in the entire season. Interestingly, she's paired with a character she seldom interacted with previously, as opposed to her usual scene partners.
- Levy, previously a one-off "joke" character, gets a major role in Boimler's segment.
- Mariner's segment features Karavitus, Asif, and Amadou of Delta Shift, who get to have more of their depth and personal motivations for antagonizing Beta Shift revealed.
- An Arm and a Leg: Asif breaks his leg in the crash, and then is forced to walk into the Rapid Aging field under the assurance that his leg will rapidly heal. Unfortunately for him, it heals wrong because they didn't set it properly first, causing it to wind up severely malformed before eventually falling off. Mariner decides to just have T'Ana grow him a new one rather than go back for the leg.
- Arbitrary Skepticism: Boimler is dismissive of Levy's Conspiracy Theorist ideas, while some are obviously random speculation like Wolf 359 being an Inside Job others are perfectly plausible given the crazy adventures any Starfleet officer experiences on a weekly basis. Indeed, Levy's talk on shapeshifting Vendorians turn out to be exactly what was happening (twice).
- Artistic License – Military:
- One of the few military tropes Star Trek usually gets right — The Chain of Command — is violated in (of all people) Boimler's story. He is assigned to an away team with Levy, who as a full Lieutenant is the ranking officer, but Boimler is on point for the entire mission (though this could be attributed to Levy's conspiracy theories making him seem a bit unreliable as a leader, since Boimler claims that this is the reason Levy hasn't been able to get promoted to Lt. Commander for an entire decade). By contrast, Mariner's story takes full advantage of her (as a Lieutenant Junior Grade) being the ranking officer amidst the Ensigns from Delta Shift.
- Delta Shift complains that they are always assigned to the night shift and their careers have suffered as a result, since they almost never have face-time with the command staff. Real Life Naval vessels have an odd number of shifts — five four-hour shifts and two two-hour dogshifts — precisely to avoid this scenario.
- Art Evolution: Reflecting the small cosmetic changes in the first season, Tendi's flashback shows the Cerritos with the same lighting scheme as it was during Season One.
- Bizarre Alien Reproduction: Thusa's species can procreate by dermal contact, where they transfer their consciousness into a protein mass that grows into a baby version of themselves in seconds.
- Breather Episode: After the reveal last episode of the mysterious ship attacking other ships and Badgey's assault on the ship, this episode focuses entirely on Beta Shift and sharing their past experiences of being trapped in caves with each other, with the mysterious ship in question never appearing or even being mentioned this time.
- Butt-Monkey: Asif gets his leg broken in the shuttle crash. He is then talked into walking into the Rapid Aging field to get at the mineral deposit, which causes him tremendous pain as his leg heals wrong at an accelerated rate, until it falls off. And then it turns out there was another way to reach the mineral deposit that simply caused people to get a dozen years younger. The rest of the team then decides to leave his leg there and have T'Ana regrow him one. At the end of the flashback, he's clearly traumatised by the experience but none of the other team members care.
- Call-Back: Tendi's "cave" story was actually the group stuck in a turbo-lift, and actually happened immediately after the end scene of the first episode. After Mariner stops chanting "Lower Decks!" they all got drunk, a turbolift stalled and they spend hours playing games.
- Cell Phones Are Useless: One of Mariner's complaints about caves is that comms always break down in them, sardonically saying how centuries of technological advancement is trumped by rocks. Turns out to have been invoked by the Vendorians in the end, having been the ones blocking communications to keep them in their trials.
- Clip Show: Parodied. The episode has all the hallmarks of such a thing: characters getting trapped somewhere, recounting past incidents as they try to get out or wait for someone to get them out. However, the past incidents are not from past episodes, they just move to infuriate the cast and the one story that helps and is from a past episode ends up being from immediately after.
- Cloning Body Parts: Mariner decides it's easier to have Dr. T'Ana grow Asif a new leg than pick up his severed one from the Rapid Aging field.
- Closed Circle: Lampshaded to hell and back with separate stories of getting trapped somewhere and having to figure out how to get out. Mariner mocks the trope of rocks always trumping their advanced technology. They can't communicate with the outside world and are unable to be beamed out, including Tendi's story of being trapped in a turbolift.
- The Cuckoolander Was Right: Steve Levy's paranoid conspiracies turn out to be right for once when the Vendorians turn out to be behind him and Boimler being trapped in a cave as a morality test. All the others, not so much. Deconstructed as shown below, as his habit of believing every outlandish thing he reads on subspace forums means no one is willing to trust his intuition when he is on to something.
- Crying Wolf: Levy is a Conspiracy Theorist who assumes that every single established piece of history is actually fabricated, and as a result is ignored by pretty much everyone. This means that when he and Boimler are trapped together in a cave, Boimler dismisses his concerns about a suspicious escape vehicle as being just another nonsensical conspiracy theory, a view not helped by an extended series of rants about Vendorians manipulating them. Not only is he correct about the escape vehicle being too convenient, but it turns out the Vendorians were manipulating them. Multiple times.
- Deconstruction: Of the Conspiracy Theorist. While previous appearances play Levy's antics up for laughs, this time they prove to be a source of frustration— Levy annoys Boimler with the thought of Vendorians being on the planet they were on despite being in a different quadrant, and when Boimler finds a possible way out, Levy blows it up. Then you find out that Levy's been stuck at his rank for around a decade and no one can stand him. Also, as it turns out, if you speculate on enough random theories eventually one or two will turn out to be true.
- Elevator Failure: The story Tendi wanted to tell is about the time the group were stuck in the turbolift for four hours moments after the events of the pilot episode.
- Express Delivery: With Thusa on the verge of dying, she transfers her consciousness into Rutherford where he gets him pregnancy and then develops inside his body in a matter of seconds, forcing T'Ana to perform a C-section on him to get Thusa out.
- Fire-Forged Friends:
- Mariner's story reveals that she was leader of a Delta Shift away team, and learns how she was maybe too rough on them and they become closer friends.
- Doctor T'Ana was stuck with Rutherford in a cave survey and says repeatedly she is not fond of engineers. After Rutherford modifies his tricorder to communicate with the growls of the creature that is chasing them, she notably softens on him.
- Tendi reveals that being trapped in the turbolift shortly after the end of the first episode of the show was an empowering experience for her, as it cemented their bond as friends and she was worried about being excluded for being Orion.
- Fountain of Youth: The chronitons emitted from the second pergium deposit (and in contrast to the Rapid Aging properties of the first deposit). Amadou briefly gets aged down to a child from the exposure.
- Framing Device: While they are trapped in a cave Boimler, Rutherford and Mariner share stories of being trapped in a cave while they use their experiences to figure out a solution to the problem.
- Giving Them the Strip: Played with, as for the first time Boimler removes his pants voluntarily, at Rutherford's request (commenting that "we're roommates" when met with a confused reaction from Mariner and Tendi), though he remarks after the fact that he probably should have given him his jacket instead.
- Glowing Flora: When Mariner kicks a moss on a stalagmite out of frustration, it starts glowing a bright green which is bright enough for the group to see in the cave. Once it the moss reveals he's sentient, he glows brighter whenever he talks.
- Green-Eyed Monster:
- Karavitus reveals in this episode that the reason Delta Shift is always so antagonistic towards Mariner and the others for seemingly no reason is that, despite getting the exact same kinds of jobs as Beta Shift, they feel like they barely get any kind of action or acknowledgement in comparison, since being on the Night Shift means that everybody else is asleep. Apparently, it's so bad that she's only ever seen people like Captain Freeman and Ransom, who are regulars in the Beta Shifters' lives, about three to five times in total, and feels like they'll never get the opportunity to rank up like Mariner and her friends did because no one else on the ship even notices that they exist, leading to them lashing out at their Day Shift counterparts over this.
- The group grow more and more jealous over how the rest of the group has apparently been growing closer with certain other members of the ship and lash out at each other over it, leading the Vendorians to work to fix their friendship.
- Green Rocks: Discussing their past experiences in caves gets Boimler to remember they can use gammanite to boost their communicator signal. While his tricorder reveals trigammanite present in the rock surrounding them, they can refine that into gammanite to use. Both variants look like vividly glowing purple minerals.
- Healing Factor:
- The carnivorous moss regrows almost instantly when parts of it are vaporized.
- Subverted in Mariner's story. Karavitus thinks that the Rapid Aging field of the first pergium deposit will act as this for Asif's broken leg, saying it will heal as he gets older. However, because his broken leg wasn't set properly first, it heals wrong as he rapidly ages, until it falls off.
- Lampshade Hanging:
- In typical Lower Decks fashion, this episode hangs a lampshade on the franchise's longstanding tradition of episodes where the characters are trapped in a cave, and how this enables the production to constantly reuse the same "cave" sets. In homage, both the framing story and all the flashbacks use the same generic "cave set" backgrounds.
- The episode opens with Mariner and Boimler delighted to learn they're being assigned to the same away mission, commenting that it's been a while. It really hasn't ("Parth Ferengi's Heart Place" was only two episodes ago) but Mariner and Boimler haven't shared a story together since the season premiere, "Twovix". This is in contrast to previous seasons pairing them up almost constantly.
- Man-Eating Plant: The moss the group is sent to study is revealed to be carnivorous and will devour anything that touches it and it's later revealed to be sentient.
- Mister Seahorse: Rutherford is impregnated thanks to Thusa having the ability to transfer her consciousness into others and quickly grow a new body. T'Ana performs a c-section before the fetus has to find (or make) somewhere to exit.
- Monster Is a Mommy: The monster that threatens Rutherford and T'Ana turns out to be protecting its child.
- Mythology Gag: In addition to Star Trek's use of caves as a budget-saving device, each plotline sends up other frequent franchise tropes:
- Boimler's adventure involves a rapidly growing moss that turns out to be a Starfish Alien.
- Mariner's involves a broken shuttle that needs to be repaired, plus the Rapid Aging and Fountain of Youth aspects.
- Rutherford's involves Monster Is a Mommy. Star Trek has also used Mister Seahorse before.
- Tendi depicts characters being stuck in a turbolift, which has happened in various Big Disaster Plots.
- Outside of the flashback plots, two of Levy's theories he believes the Vendorians are behind are the idea that warp speed damages subspace, which was the plot of the infamous TNG episode "Force of Nature", and the Klingon Civil War, which was the Season 4 finale-Season 5 opener "Redemption". The Vendorians deny their involvement in that one.
- Not Now, Kiddo: During the episode, Tendi attempts to talk about the time they were stuck in the turbolift. However, every time she does, Mariner blows her off because it wasn't applicable to their current situation. It's not until the moss speaks up and demands to hear the story that we see that it actually was.
- Passed-Over Promotion:
- It is revealed that Levy's career has been stalled out at Lieutenant for over a decade, because (as Boimler points out) nobody wants to see a raving Conspiracy Theorist in an actual command position.
- Delta Shift is actually the worst shift to be on because they have to clean up messes from previous shifts and never get to interact with the command staff. That makes it highly unlikely to get noticed and promoted like Beta Shift recently did.
- Plant Aliens: The moss that group is sent to study is revealed to be sentient, and once the group agrees to be his friend, the moss allows them to scan him while they continue to tell more cave stories.
- Rapid Aging: The pergium emits chronitons which rapidly age anyone who approaches, making it impossible to reach. The effect only lasts as long as they're in proximity. Fortunately, there's a second deposit nearby with the opposite effect but far less extreme.
- "The Reason You Suck" Speech: After Levy nukes a possible escape vehicle due to his Conspiracy Theorist tendencies, Boimler lets him have it.Boimler: Look, I know you're some sort of "outside-the-box" math genius, but do you know why you've been stuck at the same rank for, like, a decade?! No wild unfounded theories on that? Huh?! Well, it's because you're insufferable. Wolf 359 was a tragedy, Q exists, Picard isn't some hologram, and Voyager's EMH is. Ugh! You know who benefits from us being stuck in a cave? Everyone! Because they don't have to deal with you.
- Recycled Set: The episode is mostly Leaning on the Fourth Wall with regards to the franchise trope of episodes where characters get stuck in caves, providing a Closed Circle for characters to interact. A Production Nickname during the TNG-era for the studio with the cave set was dubbed "Planet Hell," which had a couple corridors and large pit they could modify according to the story. Despite being animation, all four caves in this episode are largely identical with a minor cosmetic redress, which Mariner mentions at the start that all caves are the same.
- Right for the Wrong Reasons: Levy is only right about the Vendorians entirely by chance because he's always spouting conspiracies. He almost admits that the subspace forums he reads and shares theories on are full of people making stuff up.
- Secret Test of Character: Boimler's story reveals that he and Levy were subjected to one by the Vendorians— who, as it turns out, were doing the same thing again with the current situation to convince the main four to rekindle their friendship.
- Seen It All: When T'Ana discovers that Rutherford is pregnant thanks to Thusa transferring her consciousness into him, she isn't even shocked at all and deals with the situation like it's an everyday thing.
- Shapeshifting Excludes Clothing: When Amadou briefly gets aged down to a child, his Starfleet uniform becomes noticeably oversized on his now-shrunken frame.
- Strong Family Resemblance: When Mariner starts aging she looks remarkably similar to her mother, with the same grey hair stripe and body shape.
- Surprisingly Realistic Outcome: While it hasn't completely altered the formula of the show, it's said that because of their promotions the main cast are now being sent out as the ranking officer to manage teams of ensigns. They still hang out together but are rarely being sent on away missions as a group anymore.
- Tempting Fate: Despite Mariner complaining that cave missions are terrible, Boimler tries to assure her otherwise. Cue Ransom calling to warn them of tremors.
- Traumatic C-Section: Once Rutherford gets impregnated, in order to get the baby out of him, T'Ana has to perform a C-section on him.
- Un-Paused: Mariner lets out a drawn out "Caves!" as Beta Shift beams down, which is finished when they rematerialize.
- Whole Episode Flashback: The episode consists of four flashbacks framed by a story of the Warp Core Four trapped in a cave, each of them telling a story about a previous occasion they were trapped in a cave. (Except for Tendi, who tells a story about the time she was trapped in a turbolift with the other three immediately after the events of the pilot episode.)
