This episode's plot summary may be too long or excessively detailed. (May 2022)

Flashbacks show Leah's life before the crash: she had a sexual relationship with Jeffrey, a novelist; when Jeffrey discovered that Leah had lied about being 18 years old, he immediately broke off the relationship.

Leah tells the others about Jeanette's phone, but does not tell them she called Jeffrey. Rachel is furious that Jeanette had a working phone and didn't tell the others about it. Toni becomes jealous of Shelby and Martha's growing friendship. Rachel leads an expedition to the top of a hill to get a view of the island, planning to use Fatin's mirror to signal for help. Rachel accidentally throws the mirror over a cliff edge during an argument; Leah riskily tries to retrieve it, but fails. Meanwhile, Gretchen continues to watch the girls, and arranges for them to discover a bag containing medicine, ostensibly belonging to the crashed plane's pilot.

Flashbacks show Rachel's past; she was a competitive diver whose coach told her she didn't have the body for the sport. This hits hard for Rachel, who develops severe bulimia trying to lose weight, straining her relationship with her sister Nora; she hits her head and falls during a crucial dive.

Dot and Shelby search for shelter for the group and bond along the way before eventually finding a cave. Meanwhile, Rachel, Leah and Nora swim out to the plane wreckage in an attempt to find more supplies. Rachel and Leah make numerous dives in an attempt to retrieve the plane's flight recorder; Rachel nearly drowns Leah by holding her underwater. They eventually retrieve the flight recorder and the girls argue over whether to open it; they eventually vote to open it, and listen to the recording of the pilot calling for help as the plane crashes.

Flashbacks show Dot's past; she sold drugs to students at her and Shelby’s school (including Shelby's cheating boyfriend) while caring for her ailing father, Tim. Tim eventually asks Dot to euthanize him, which she reluctantly does; his last request is for her to go on the Dawn of Eve retreat. Later, Gretchen meets with Dot and offers her the trip for free. Dot cynically responds that nothing is free, and wonders what Gretchen really wants from her.

When a bag of chips washes ashore, the girls have a shelter-building contest to determine who gets it. Leah clashes with Fatin over the latter's lack of effort and they fight; Leah shoves Fatin after she teases her about her relationship with Jeffrey. Toni continues to clash with Shelby about her attempts to take charge, and with Martha over her budding friendship with Shelby. She eventually loses control and wrecks their team's shelter in anger, upsetting Martha, who says she's tired of picking up the pieces after her. That night, Fatin leaves the newly-constructed shelter in anger after an argument with Leah.

Flashbacks show that Toni is in the foster system as her mother is in rehab. At school, Toni starts dating new girl Regan, but they break up due to Toni's short temper and inability to walk away from conflict. After their breakup, Martha comforts Toni and invites her to stay at her house.

The next morning, Fatin is still missing, and Toni finds some of Fatin's clothing bloodstained. The group venture into the forest to search for her, with Nora staying behind to tend to the fire. Whilst looking for Fatin, Rachel gets stuck in a puddle of mud, and the others manage to save her. At the same time, Nora prevents the fire from burning out by burning some pages of a journal. Eventually they find Fatin, who has discovered a pond, finally giving the girls a source of fresh water; observing them, Gretchen notes the milestone. Back at camp, Fatin and Leah reconcile and burn Leah's copy of Jeffrey's book. That night, the girls go to bury Jeanette's body deeper, but discover it missing.

Flashbacks reveal Fatin is a star cellist, forced to continue playing by her overbearing mother. When she discovers her father cheating on her mother, she publicly shames him by sending his nude photos to all his contacts; however, her mother takes her father's side, and they decide to transfer Fatin to a religious boarding school after she returns from the retreat.

Jeanette's body is transported back to Gretchen. Rachel discovers mussels, providing a feast for all except Shelby, who claims to be allergic. Shelby's poorly-concealed homophobia toward Toni is criticized by the others. Soon all except Shelby develop food poisoning from the mussels, with Toni suffering the worst symptoms. Leah goes to retrieve the bag of medicine; but seeing Shelby behaving suspiciously, she briefly drops the bag to follow her, losing some of the pills. Once they return, Shelby forces Toni to take the only remaining anti-nausea pill. That night, Martha faints, and Leah admits she lost some of the pills. Meanwhile, Gretchen admits herself into a psychiatric hospital in order to meet Faber and offer him a job.

In flashbacks, Leah's friend Ian tries to kiss her during a camping trip, but she storms off when he criticizes Jeffrey's treatment of her; later, she accuses Ian of telling Jeffrey she was under 18. Leah is later hit by a car after attending a party; at the hospital her parents express their worries about her depression.

A high tide floods the beach, washing many of the girls' supplies out to sea; they move camp to another location. Shelby finds two more suitcases "washed up", full of valuable supplies; suspicious of the convenient discovery and Shelby's secretive behavior, Leah accuses Shelby of knowing something about their situation. Shelby reveals her secret—she is missing two teeth and wears dentures. Apart from the group, Toni advises Shelby to take advantage of the opportunity to be free from her family's expectations, and Shelby kisses her. Meanwhile, Nora reveals that Rachel was cut from the diving team and is not going to Stanford, causing the two to fight until Dot puts a stop to it. Later, a plane flies over the island and notices the girls, giving them hope of rescue.

Gretchen pulls strings to prevent the pilot who saw the girls from rescuing them. The girls, believing rescue is imminent, eat most of their remaining food, including some cannabis edibles. High, the girls discuss plans for their lives after being rescued. Toni assures Shelby that she didn't tell Martha about their kiss. Rachel acknowledges her time as a diver is done. In the woods, Martha spots Alex, one of Gretchen's assistants, but under the influence of cannabis she mistakes him for a mannequin; and when she brings the other girls to show them, the mannequin has been placed there. That night, Shelby cuts off some of her hair while having a mental breakdown. Later, Leah apologizes to Shelby for suspecting her.

Flashbacks depict Shelby's life as a teen beauty pageant participant; her controlling father runs conversion therapy sessions. Trying on dresses for a pageant, Shelby kisses her best friend, Becca; after her parents find out, Shelby asks Becca to stay away from her. Later, she learns that Becca has committed suicide.

Rescue has not arrived, and the girls have been out of food for two days. Toni, Martha and Shelby forage for food in the woods. To Martha's disgust, Shelby suggests they kill an animal. Martha lets a goat escape, angering the others, but later finds it on her own and kills it. Shelby and Toni find a lychee tree; the two kiss again and then have sex. Meanwhile, Nora realizes that Rachel is now afraid of swimming and tries to persuade her to return to the water. Suspicious and delirious, Leah tries to swim away from the island; Rachel dives in and saves her from drowning. That night, Leah discovers Nora talking to Gretchen's team—she is the surviving informant.

Flashbacks show that Martha was one of several girls sexually abused by a doctor who helped her after an injury, but remains in denial about it. Martha initially refuses to testify against him; eventually, once she agrees to speak to the grand jury, she lies and says he didn't do anything.

The next morning, Shelby tells Toni she enjoyed their night, but that she isn't ready to talk about it. Martha gets the others to help her carry the goat to camp. Leah pretends not to remember anything from the night before, but follows Nora into the woods to search for hidden cameras; Nora tricks her into falling into a pit. Shelby and Toni talk about their feelings for each other. Leah escapes from the pit and returns to camp, but before she can tell the others about Nora's betrayal, Rachel is attacked by a shark and Nora runs into the water to save her.

Flashbacks show Nora dating a boy named Quinn over the summer, but breaking up with him because Rachel dislikes him. In the fall, Nora discovers Quinn was killed in a hazing accident. She meets Gretchen and discovers Quinn was killed by her son; Gretchen then recruits Nora into her study.

Rachel loses her right hand to the shark attack, and Nora is swept out to sea trying to rescue her and presumed dead. As the girls move their camp inland, Rachel is stunned with grief. Unable to prove to the others that Nora knew they were stranded intentionally, Leah tries to get information about Nora from Rachel; Rachel lashes out at her, blaming herself for her sister's death. Eventually, Dot persuades Rachel to move inland with the others. Meanwhile, a parallel experiment has begun with nine boys on an island: Rafael, Josh, Scotty, Bo, Kirin, Ivan, Henry, Seth, and DJ. On their first day stranded, they split up to search the island, and reunite to find DJ dead, his body apparently mutilated by a wild animal. Unknown to them, DJ's death was faked; he is Gretchen's son Devon, who killed Nora's love interest, Quinn.

Food supplies are running low on the boys' island. Rafael spills a jar of salsa and, embarrassed, flees to the woods. Seth joins him, and together they find an underground bunker stocked with food and beer. Seth gives Rafael credit for the discovery, making him the hero of the day. On the girls' island, Rachel and Leah reconcile and find a crate of party supplies in the sea, while Martha is irritated by Toni's attempts to make her and Shelby closer.

Flashbacks show Rafael's life before the trip: he commuted from Tijuana to attend a private school in San Diego, where his girlfriend Marisol was the daughter of wealthy philanthropists. Rafael skipped his own family obligations to attend a charity gala with Marisol's family, but en route he got into an altercation with another motorist, was jailed by Customs and Border Protection, and was bailed out the next day by Marisol's parents.

At night, the boys hear a jaguar prowling around their camp. Hiding their food supply from the animal, Scotty persuades Bo to steal some jerky for themselves, concerned that the others may not be trustworthy. The next night, as the boys camp on a narrow ledge, Ivan retaliates against Kirin's homophobic jokes by revealing to the others that Kirin has gonorrhea. Worried that the jaguar will be attracted to the smell of the stolen food, and feeling guilty about stealing from the group, Bo leaves the ledge to return it; he and Scotty narrowly escape the animal on their return. Meanwhile, Toni is almost hit by a falling tree limb, and Martha confesses her fear of sex to Fatin.

Flashbacks show Scotty and Bo were best friends in Florida, but Bo had to scrupulously hide any trace of their activities from his abusive and hyper-controlling parents. When one of Scotty's money-making schemes, buying some t-shirts to resell, accidentally led to Bo's father's lawnmower being flooded in a rainstorm, Bo was beaten for it. Later, the two of them vandalized a house that had been Scotty's childhood home.

The girls throw a birthday party for Dot on the beach. When Rachel's grief for Nora resurges in the evening, Shelby commiserates with her and tells her how she used prayer to cope with her grief over Becca. Meanwhile, Seth organizes the boys to kill the jaguar: they line the bunker with sharpened stakes, cover it with leaves, and leave a small dead animal on top as bait. After the jaguar falls into the trap, Kirin stabs it to death with a spear carved by Ivan. At their victory party that evening, Kirin pantses Seth, and Seth storms away in embarrassment. Josh approaches him to sympathize, having been a bullying victim himself, but Seth shoos him away.

Seth, who is Gretchen's second confederate on the island, records a message characterizing Josh as fragile and unstable. When the boys split up to search for fresh water, Seth destroys the hidden microphones on the beach. After Kirin and Josh discover a lake, Josh tells Kirin that he was assaulted by Seth. When the group reconvenes on the beach, Kirin publicly accuses Seth. Only Rafael believes Seth's claims of innocence; the others vote to banish Seth from the group. That night, Josh asks the group to promise never to reveal what happened to him. Meanwhile, the girls hold a funeral for Nora. Fatin persuades Leah to try to let go of her suspicions of Nora, but Fatin herself finds hidden notes in Nora's belongings that incite her own suspicions. After the funeral, Rachel sits on the beach, mourning, while Nora, alive and well, watches her via the monitors at Gretchen's headquarters.

When Shelby says "I love you" to Toni for the first time, Toni panics, but Martha reminds her to find value in herself, giving her the confidence to tell Shelby she loves her too. Leah begins experiencing hallucinations of Ben Folds. When Martha finds that her hunting snares have killed a mother rabbit with nursing babies, she has a nervous breakdown and kills the babies as well. When the boys find that Seth has their only lighter, they track him down and take it back; Ivan and Rafael are disturbed by the violence with which Seth is treated. After Rafael takes pity on Seth and brings him fresh water and a sweater, Josh insists on exiling him from the camp as well; Ivan self-exiles to bring Rafael and Seth a candle on a cold night.

Flashbacks show Ivan's campaign to get Kirin's lacrosse coach fired for wearing a blackface Halloween costume. When he found Kirin mourning the coach's career, Ivan baited him into a homophobic rant to get him expelled from school; Ivan's boyfriend left him in disgust, leaving a note saying "Be tender".