Marin hasn't spoken to anyone from her old life since the day she left everything behind. No one knows the truth about those final weeks. Not even her best friend, Mabel. But even thousands of miles away from the California coast, at college in New York, Marin still feels the pull of the life and tragedy she's tried to outrun. Now, months later, alone in an emptied dorm for winter break, Marin waits. Mabel is coming to visit, and Marin will be forced to face everything that's been left unsaid and finally confront the loneliness that has made a home in her heart.

Kaeleigh and Raeanne are 16-year-old identical twins. Everything on the surface seems fine, but underneath run very deep and damaging secrets. When the girls were 9, Daddy turned to his beloved Kaeleigh in ways a father never should. Raeanne needs to numb the pain of not being Daddy's favorite; Kaeleigh wants to do everything she can to feel something normal, even if it means cutting herself and vomiting after every binge.

Lia and Cassie were best friends, wintergirls frozen in matchstick bodies. But now Cassie is dead. Lia's mother is busy saving other people's lives.Her father is away on business. Her stepmother is clueless. And the voice inside Lia's head keeps telling her to remain in control, stay strong, lose more, weigh less. If she keeps on going this way - thin, thinner, thinnest - maybe she'll disappear altogether.

Theodore Finch is fascinated by death, and he constantly thinks of ways he might kill himself. But each time, something good, no matter how small, stops him. Violet Markey lives for the future, counting the days until graduation, when she can escape her Indiana town and her aching grief in the wake of her sister's recent death. When Finch and Violet meet on the ledge of the bell tower at school, it's unclear who saves whom.

Pay close attention, and you might solve this. On Monday afternoon five students at Bayview High walk into detention. Bronwyn, the brain, is Yale-bound and never breaks a rule. Addy, the beauty, is the picture-perfect homecoming princess. Nate, the criminal, is already on probation for dealing. Cooper, the athlete, is the all-star baseball pitcher. And Simon, the outcast, is the creator of Bayview High's notorious gossip app. Only Simon never makes it out of that classroom. Before the end of detention, Simon's dead.