Thomas Webb, a young college dropout, is navigating the uncertainties of his future while caught in a frustrating crush on his friend Mimi. As he forms an unexpected friendship with his enigmatic neighbor, W.F., he starts to unravel the complex fabric of life. Through his interactions with W.F., Thomas gains insights that challenge his understanding of relationships and adulthood.
One fateful night at a bar, Thomas is taken aback when he sees his father, Ethan, a publisher, sharing an intimate moment with Johanna. Concerned that this interlude may devastate his mentally fragile mother, Judith, he becomes obsessed with digging deeper into Johanna's connection to his family. When he finally confronts her, he learns that she is an editor working with his father and has seen his photographs at Ethan's office.
Johanna's piercing remarks cut to the core of Thomas's insecurities, suggesting that he is still a naïve boy unaware of life's intricacies, while also hinting at a mutual attraction. Torn between feelings for both Johanna and Mimi, Thomas eventually confides in W.F. about his burgeoning feelings for Johanna.
At an event hosted by friends, Thomas finds Johanna with another man and reacts harshly, calling her a "hooker." However, she calmly explains the situation, and in a burst of impulse, he kisses her. As their relationship progresses, Thomas reveals to her his dreams of becoming a writer, yet he is met with critical feedback from Ethan about his writing being merely "serviceable."
Unbeknownst to Thomas, W.F. is a successful but reclusive writer, and his conversations with Thomas reignite his passion for writing. When Thomas comes across a manuscript titled The Only Living Boy in New York in his apartment, he is shocked to learn about W.F.'s true identity.
As the storytelling takes us to a gathering at Ethan's workplace, tension escalates when Thomas invites both W.F. and Mimi. Mimi unexpectedly opens up about her feelings, further complicating Thomas's affections for Johanna. When he attempts to introduce W.F. to Judith, W.F. mysteriously disappears. Later, W.F. warns Johanna to treat Thomas gently during a rooftop encounter, signaling the fragile state of their intertwined lives.
The chaos of emotions culminates when Ethan proposes to Johanna, leading Thomas to feel betrayed, especially when Johanna admits her feelings for his father, shattering any illusions he had about their relationship. A confrontation with W.F. reveals intricate secrets about paternity and the power dynamics within Thomas's family, making him realize the weight of expectations he has been living under.
In the midst of unraveling familial ties, Ethan's decision to pursue divorce only complicates feelings further as Thomas grapples with his complicated emotions. Through these tribulations, he finds solace in the written word, attempting to express his turmoil creatively.
A year later, an unexpected reunion with Ethan at a bookstore offers a moment of reckoning. As Ethan confesses lingering feelings for Johanna, Thomas is left to reflect on his own journey. The narrative concludes with the poignant reunion of Judith and W.F. during a literary reading, their story finally catching a break. Watching their love story unfold, Thomas is stuck between sadness and acceptance, gaining clarity about himself and his family's complex narrative, which ultimately fosters a sense of purpose within him.
