Nine teenage girls are en route to Hawaii when their plane fails, leaving them stranded on a remote island. Among them we meet Leah, who has survived to tell their story to a pair of federal investigators. Flashbacks offer an intimate look at Leah’s pre-island life, and the taboo relationship that broke her heart.

The castaways are still reeling after Jeanette's death. Frustrated by everyone else's inaction, Rachel leads an expedition to the island's summit to get a lay of the land. We learn more about her career as an elite athlete.

Leah, Rachel, and Nora swim out to the plane wreckage to search for supplies, while Dot and Shelby search for a cave that might provide better shelter. Flashbacks reveal Dot's life before the crash.

A friendly shelter-building contest to win a much coveted snack turns ugly. Toni provokes strife on her team.

When one of the castaways goes missing, a search party heads out to find her. We learn more about Fatin's past, which isn't exactly what the other girls has assumed.

A sudden illness rips through the beach camp, affecting nearly every castaway. As the girls fight for survival, we learn more about Leah's past and how she’s been faring since her rescue.

A tidal surge forces the castaways to relocate their camp. Still suspicious of the island and how they got there, Leah turns her paranoia on one of the other girls, viciously accusing her of knowing more than she's letting on. In flashback, Jeanette's astonishing backstory is unveiled.

Assuming that rescue is imminent, the castaways let loose. The only girl who doesn't feel festive is Shelby, and a look into her past reveals why.

Starvation becomes a very real possibility for the weakened girls, but when a scavenging trip becomes a hunting party Martha objects. Leah's paranoia about the island escalates to a fever pitch.