Alice Hughes, portrayed by Meryl Streep, is a celebrated Pulitzer Prize-winning author currently engaged in crafting her latest manuscript, which her publisher hopes will be a follow-up to her renowned book, You Always/You Never. As Alice prepares to accept a literary award in the UK, she faces an obstacle: her health prevents her from flying. In a bid to resolve this predicament, her agent Karen suggests that Alice embark on a transatlantic journey aboard the Queen Mary 2. To assist her during this voyage, Alice invites her nephew Tyler, along with two old university friends, Roberta and Susan, whom she has not connected with in years.
Throughout the trip, Roberta and Susan navigate their own lives—Susan lives with her son Eddie while Roberta works as a salesgirl at a department store. Tensions arise between Alice and Roberta due to Roberta's conviction that Alice incorporated personal elements about her into You Always/You Never, which Roberta feels led to her personal misfortunes. Confiding in Susan, Roberta reveals her bitterness, exclaiming that she gained nothing positive from the experience.
Unbeknownst to Alice, Karen boards the ship with ulterior motives, hoping to extract information about Alice's new book, as both she and the publisher are in the dark regarding its content. Their strong desire is for Alice to pen a sequel to her earlier success, You Always/You Never.
Once aboard, a budding friendship develops between Karen and Tyler, with Karen leveraging this to glean insights from Alice. Alice hints to Tyler that her new book centers on the idea of "trying to catch lightning in a bottle for a second time," suggesting its ties to her previous work. While Alice immerses herself in writing, indulging only in meals and swimming, Roberta sets out to attract wealthy suitors on board—enthusiastically urging Tyler to investigate their backgrounds for any criminal activities. Meanwhile, Susan begins to meet Kelvin Krantz, an established mystery and thriller writer, whom Alice regards with disdain despite reading his novels in secret.
As Roberta avoids Alice, Karen continues her friendly pursuit of Tyler, and a growing connection forms between them. Their excursions to the planetarium and disco deepen their bond. Tyler, however, becomes curious when he spots a mysterious man exiting Alice's quarters, leading to rampant speculation about Alice's potential romantic entanglements. Karen opens up to Tyler regarding her past relationship with Jan, expressing her fears about her future following their recent breakup, especially concerning her dreams of motherhood.
Roberta ultimately seeks a long-overdue apology from Alice regarding the alleged appropriation of her life experiences, yet their efforts to connect prove futile—an appointment at the tearoom becomes thwarted by Roberta's decision to date a wealthy gentleman instead, leaving Alice feeling dejected and betrayed.
After a confrontation with Alice over her new project, tensions reach a climax during a dinner gathering, during which both women’s resentments surge to the surface. Susan steps in, chastising them for clinging to their grudges. Suddenly faced with the knowledge that her book may not resonate with the expectations placed upon it, Alice contemplates deleting her work that all anticipated to be a sequel to You Always/You Never.
When the voyage concludes, Alice and Roberta finally share a moment of reflection concerning their fractured relationship. Roberta offers to provide Alice with the necessary life details for writing her sequel but demands a 30% share of the profits—a proposal Alice rebuffs. As they part ways, Roberta’s parting words echo in Alice’s mind, "I loved you when you were Al."
Embracing her creativity anew, Alice commences a fresh writing endeavor. Unfortunately, the following morning brings devastating news to Tyler—he is approached by Dr. Mitchell, Alice's personal physician, revealing that Alice has succumbed to deep vein thrombosis during the night.
In the aftermath, Tyler, Roberta, and Susan pay homage at the grave of 19th-century author Blodwyn Pugh, honoring Alice's wishes. Back in the United States, Roberta gives Alice's unpublished works to Karen, hoping to profit off of them; however, Karen dismisses the pieces as unsuitable for publication while supporting Roberta’s ambition to write about her life experiences. Meanwhile, Susan collaborates with Krantz on a book inspired by a concept she once shared aboard the ship. Tyler returns Alice's unfinished work to her apartment, reflecting on her appreciation for consciousness and how people can profoundly influence one another’s lives.
