As the school mourns the death of Hannah Baker, her friend Clay receives a box of tapes with messages she recorded before she committed suicide.
Hannah makes friends with Jessica and Alex, two other new students. Justin doesn't show up at school, and Hannah's mother finds something troubling.
Jealousy and gossip take a toll on Hannah's relationships. As Alex struggles with feelings regret, the guys pressure Clay into getting drunk.
Hannah thinks someone is stalking her and sets a trap. Hannah's mother confronts the principal, and Clay strikes back at someone who wronged Hannah.
Hannah and Clay connect at the school dance, but a crass rumor ruins the mood. Clay takes Courtney to visit Hannah's grave.
Hannah's date on Valentine's Day doens't go as planned. Alex gets in a big fight at school and has to face the honor board.
Another student sabotages Hannah during a class project. Clay's nightmares about Hannah spill over into the daytime.
Inspired by a friend's poetry reading, Hannah pours her heart out. Tony confides in Clay about the night of Hannah's death.
Hannah witnesses a traumatic event at a summertime party. Clay tries to reason with Justin, and Marcus warns him that the worst is yet to come.
A distraught Hannah gets a ride home from the party. Jessica's behavior grows increasingly erratic, and Clay learns the truth behind a tragedy.
Clay and Hannah grow closer. While Clay spends a heartbraking night listening to his tape with Tony, tensions boil over at Bryce's house.
Hannah winds up at a party after an argument with her parents. The students are served with subpoenas, and Justin wrestles with conflicting loyalties.
Hannah seeks help from Mr. Porter, the school counselor. Clay plays the new tape for Tony and weighs what to do next.