Hazel Grace Lancaster—a 16-year-old with cancer that has spread to her lungs—attends a cancer patient support group at her mother’s behest. At first she hesitates because she feels like it has done her nothing. She thinks attending the support group could be the worst part of her life, until a particular support meeting, Hazel meets a 17-year-old boy named Augustus Waters, whose osteosarcoma caused him to lose his right leg, which was replaced with a prosthetic. Augustus is at the meeting to support his friend, Isaac, whose only remaining eye is soon to be removed due to cancer.
Hazel and Augustus strike a bond immediately and agree to read each other’s favorite novels. Augustus gives Hazel The Price of Dawn, and Hazel recommends An Imperial Affliction, a novel written by Peter Van Houten, who lives in Amsterdam, about a cancer-stricken girl named Anna that parallels Hazel’s own experience. After Augustus finishes reading her book, he is frustrated upon learning that the novel ends abruptly without a conclusion. Hazel explains the novel’s author had retreated following the novel’s publication and has not been heard from since.
A year later, Augustus reveals to Hazel that he has tracked down Van Houten’s assistant, Lidewij, and, through her, has managed to start an e-mail correspondence with Van Houten. The two write to Van Houten with questions regarding the novel’s ending and the fate of the mother of Anna. Van Houten eventually replies, explaining that he can only answer Hazel’s questions in person. At a picnic, Augustus surprises Hazel with tickets to Amsterdam to meet Van Houten.
While in Amsterdam, Augustus confesses his love for Hazel. Hazel and Augustus finally meet Van Houten but are shocked to find that he is a mean-spirited drunk. Horrified by Van Houten’s behavior, Lidewij confesses to having arranged the meeting on his behalf, angering Van Houten, who proceeds to insult Hazel’s cancer, starting an argument and causing Hazel and Augustus to flee from the drunken author’s home.
Augustus confesses that his cancer has returned. The two affirm their love and support for each other. Upon their return to Indianapolis, Augustus’s health worsens and he ends up in the ICU for a few days. Fearing his death, Augustus invites Isaac and Hazel to his pre-funeral, where they give eulogies. An extremely sick Augustus dies soon after. This leaves Hazel heartbroken and she doesn’t know what to do with herself. After this traumatic event, Van Houten shows up at Augustus’s funeral to apologize to Hazel.
Hazel learns that Augustus was writing a sequel to An Imperial Affliction. Hazel reads Augustus’s words. He says getting hurt in this world is inevitable, but we do get to choose who we allow to hurt us, and that he is happy with his choice, and hopes she likes her choice too. The book closes with Hazel stating that she is happy with her choice.