Elliott, a 23-year-old man portrayed by Jeremy Allen White, finds himself facing a daunting diagnosis of Ewing sarcoma, a rare form of bone cancer that he initially confuses with a sexually transmitted disease. His journey begins when he strikes up a connection with Mia, played by Maika Monroe, at a New York City sandwich shop where they both work. During their first date, Elliott bravely shares his diagnosis with Mia, laying a strong foundation for their relationship as they embark on a romantic journey together.
As their bond deepens, Mia supports Elliott through the challenges of his illness, traveling with him to New Jersey to inform his parents about his condition. With unwavering commitment, she even leaves her marketing job to be by his side as he undergoes difficult chemotherapy treatments, which take a toll on both his physical and mental health. Meanwhile, tension arises as Elliott starts to drift away from his best friend and roommate, Nico, played by DeRon Horton. When chemotherapy fails to work as hoped, Elliott faces surgery with a slim chance of success. In what could be their final days together, they take on exciting activities from Elliott’s bucket list and decide to marry quickly before his operation.
Miraculously, Elliott survives the surgery, and his cancer enters remission. Four months later, he and Mia have moved in together, where Elliott begins studying software design and Mia finds a new job that she loves. However, as they settle into their marriage, they begin to face challenges brought on by their familiarity with each other. A visit to Mia’s mother, Tracy, portrayed by Gina Gershon, introduces doubts about their marriage's long-term prospects. Tensions mount when Mia opts to skip Elliott’s vital cancer screening for a work presentation, leaving him feeling unsupported. To cope with his feelings of distance from Mia, Elliott joins a support group for cancer survivors, leading to further separation between them. As Elliott reconnects with Nico and flirts with women, Mia finds herself drawn to her boss, David, played by Sendhil Ramamurthy.
An accidental call reveals Elliott's night out with Nico and other women, prompting an emotional confrontation with Mia, who pleads for them to mend their relationship. Unfortunately, Elliott harshly admits that their marriage may not have happened without his illness, devastating Mia. Seeking comfort, she shares a kiss with David.
As the days pass, Elliott and Mia decide to separate, and Elliott moves out of their shared apartment, abandoning his aspirations in software to return to his old job at the sandwich shop. In the midst of their breakup, Mia resolves not to pursue a relationship with David and struggles with the complexities of dating while still coping with her feelings for Elliott. Meanwhile, Elliott grapples with his own dating challenges. In a moment of vulnerability, he reaches out to Mia, and they agree to meet to discuss their future. During this heartfelt reunion, Elliott apologizes for his earlier words and expresses a desire to reconcile, but Mia, while still loving him, asks for a divorce, feeling uncertain about their compatibility. Elliott acquiesces but wishes to remain friends.
In a poignant moment, they share a kiss and try to part ways, only to discover that they are both headed to the same subway station, granting them a chance to reflect on the memories they created together.
