The first tape is addressed to Justin Foley, Hannah’s first kiss. She addresses the first time they kissed after meeting in a playground in their town, and explains that it was nice and completely innocent. However, she also explains that Justin later bragged to his friends that more had happened in the park, and Hannah was called a slut for the rest of high school. At this point, Clay pauses the tapes and goes to his friend Tony’s house, where he borrows his portable Walkman so that he can listen to the tapes while following the locations of each of Hannah’s stories. The locations are designated on a map that she slipped into the lockers of each recipient before her death.
The second tape is addressed to Alex Standall, who compiled a list during Hannah’s freshman year that declared she had the best ass in the freshman class. Hannah explains that the title led to a boy assaulting her in the local candy store, only adding to her feelings of insecurity after being labeled a slut.
The fourth tape is addressed to Tyler Down, who stalked Hannah outside of her bedroom window and took pictures of her. In addition to Tyler, however, the tape also addresses an unnamed girl who Hannah knew somewhat well, and whose help she enlisted to help catch the Peeping Tom. The unnamed girl decided to give Tyler a show, first asking Hannah to give her a back massage and then exclaiming over nonexistent sex toys that she “found” in Hannah’s drawer. Hannah felt violated by Tyler as her privacy had been infringed on, but she moves on to address the unnamed girl next.
The story of Courtney Crimsen is told in the fifth tape. She is known as a sweet, well-liked girl, a persona which Hannah explains that she fell for. Following the event with Tyler, however, Hannah began to feel ignored by Courtney, and even when Courtney invited her to a party she still felt suspicious. Courtney abandoned her at the party, and later Hannah found out that Courtney had been spreading lies about the “surprises” she’d found in Hannah’s drawer.
The sixth tape is addressed to Marcus Cooley, who Hannah matched with in a set of school Valentines. He showed up late to a date for ice cream that she organized, and then molested her in a booth at the diner where they had met.
The seventh tape is addressed to Zach Dempsey. Hannah explains that in her Peer Communications class, there was a set of bags at the back of the room where students could leave compliments for each other. After her assault in the diner, Zach comforted her. However, she later discovered that he had been removing notes from her bag. By this point, Hannah explains, she was already depressed, and that action only worsened her condition. She also explains that she wrote an anonymous note to her Peer Communications class, in which she shared that she had been feeling suicidal. No one in the class took the note seriously at all, instead thinking that it was made up for attention.
The eighth tape is addressed to Ryan Shaver, who attended a poetry class with Hannah while she was spiraling further into depression. They shared their poetry with each other, including a poem that Hannah wrote about not being able to accept herself. Ryan later anonymously published the poem in his magazine, The Lost and Found Gazette, betraying Hannah’s trust.
The tenth tape is addressed to Justin again. Hannah explains that on the night of the party, he allowed his friend to enter a room where a drunk, unconscious girl was laying and rape her. Hannah does not name the boy who committed the rape; she explains that if she named him, he would skip town and stop the chain of tapes. However, she blames Justin, to a certain extent, for allowing the boy into the room in the first place.
The eleventh tape is addressed to Jenny Kurtz, who gave Hannah a ride home the night of the party and hit a stop sign. Later, a car crash happened at the intersection, due to the stop sign not being there, and a senior at Hannah’s school was killed. The day of his funeral led Hannah to start thinking about her own funeral.
The twelfth tape is addressed to Bryce Walker, who sexually assaulted Hannah in a hot tub at the party before she left. It is on this tape that Hannah begins discussing how she planned to kill herself.
The thirteenth tape is addressed to Mr. Porter, an English teacher that filled in as a guidance counselor for a period of time at Hannah’s school. She went to him with her feelings of depression and isolation, and he did nothing to help her.
As the tapes are played, Clay walks to each location that Hannah discusses, feeling more and more distressed as he does so. By the end of the tapes, he feels changed, and the novel ends with him addressing a student named Skye, who he sees behaving like Hannah, potentially preventing another suicide.