In the midst of her battle with thyroid cancer that has spread to her lungs, Hazel Grace Lancaster finds herself grappling with the tough realities of her life. Despite her struggles, her mother encourages her to attend a weekly support group for young cancer patients, believing that it might help her cope with her depression.
During one of these sessions, Hazel meets Augustus "Gus" Waters, a charming and witty young man who, despite having lost a leg to bone cancer, remains hopeful as he is now in remission. Gus is at the meeting to support his friend Isaac, who is enduring his own challenges with eye cancer.
As Hazel and Gus spend more time together, they develop an unexpected friendship rooted in their shared experiences and interests. They embark on a literary exchange, with Gus delighting Hazel by gifting her "The Prince of Dawn" and Hazel recommending "An Imperial Affliction," a striking novel about a young girl named Anna facing the trials of cancer—a story that resonates deeply with Hazel and ends on a note that leaves readers with a longing for closure.
Weeks pass, and Gus reveals an exciting secret: he has managed to get in touch with the reclusive author of "An Imperial Affliction," Peter Van Houten. However, Van Houten insists on answering their questions face-to-face, leading Gus to surprise Hazel with tickets to Amsterdam, organized through a wish-granting foundation.
After receiving medical clearance, they arrive in Amsterdam, where Gus treats Hazel to a romantic dinner funded by Van Houten. Their excitement quickly turns to disappointment when they meet the author, discovering he is nothing like they imagined—he is rude and dismissive, and it later comes to light that his assistant, Lidewij, had orchestrated the meeting without his knowledge. This disillusionment leaves Hazel feeling insulted, not only due to the author's behavior but also because of her own health struggles.
With their hearts heavy, Hazel and Gus leave Van Houten’s home, but Lidewij offers a way to redeem their experience with a sightseeing tour. During their visit to the Anne Frank House, they share a magical first kiss, paving the way for a deeper intimacy when they return to Gus’s hotel room, marking a pivotal moment in their romantic relationship.
However, their joy is cut short when Gus reveals that his cancer has returned and is now terminal. As their journey back to Indianapolis is filled with heartache, Gus organizes a "pre-funeral" attended by both Hazel and Isaac, where he asks them to deliver eulogies. In a poignant moment, Hazel tells Gus that she wouldn’t trade their precious time together for anything. Tragically, just eight days later, Gus passes away.
At his funeral, an unexpected visitor arrives: Van Houten, who appears burdened by guilt and shame. He discloses that Gus had one last wish for him — to attend Hazel's funeral and apologize for his previous actions. A heartfelt admission follows, revealing the tragedy of Van Houten's own daughter, Anna, who lost her fight against leukemia.
In a touching moment, Van Houten hands Hazel a crumpled note. Initially rejecting it, she later feels compelled to read it after coaxing from Isaac. As she unfolds the words penned by Gus, a poignant farewell surges through her heart, encapsulating his love and lingering connection to her.
As she lies in her backyard, eyes turned to the starry sky, Hazel feels a fleeting sense of peace wash over her—a gentle reminder of Gus’s enduring love, illuminating her path even amidst her grief.
