New Orleans, 1988. After Roy (Ben Foster), a seasoned hitman, receives a devastating diagnosis of terminal lung cancer, he storms out of his doctor's office in frustration. He decides to return to his hometown of Galveston, where he plots his revenge against those who betrayed him in a sting operation that led to his downfall—he had been sent to retrieve incriminating evidence from a lawyer. A heavy-drinking enforcer for his boss Stan Pitco (Beau Bridges), Roy has been double-crossed in a scheme that leaves him fighting for his life. In a desperate act of survival, he manages to kill his would-be assassins, but his fate takes a turn when he discovers Rocky (Elle Fanning), a young escort held against her will, and decides to take her along on his escape.
As they drive towards Orange, Texas, Rocky reveals her naivety; she believed she was entering a legitimate business after finding it in the yellow pages, introduced by a friend as self-employment. Roy, though drawn to her plight, maintains his boundaries, even rejecting her offers of intimacy. He delves into the incriminating papers he salvaged from the lawyer’s residence, trying to unravel the mess in which he's become entangled.
In a shocking twist, Rocky reveals that her daughter, Tiffany (Lili Reinhart), is actually the child of her abusive stepfather, whom she shot and killed. After settling into a motel in Galveston, Roy spends quality time with Rocky and Tiffany, creating a fleeting sense of family and safety. When he leaves them to reconnect with his past love, Loraine (Adepero Oduye), he returns to a disheartening discovery: Rocky, thinking she was abandoned, has returned to escorting.
Fueled by his growing affection for Rocky, Roy confronts the truth of their situation head-on as he learns of the dangers lurking in their past. He then decides to leverage the incriminating evidence he possesses against his former boss, demanding a large sum to keep quiet and ensure their safety. He encourages Rocky to pursue an education, dreaming of a brighter future for them amid the chaos.
However, their hopes for a peaceful life come crashing down when they are captured by Pitco's crew. Separated and brutalized, Roy narrowly escapes with the help of a woman from his past. Tragically, he finds Rocky dead, a victim of unimaginable violence. Devastated, he flees, only to wake up in a hospital, where he learns the diagnosis was incorrect; he suffers from Aspergillosis, a condition that is treatable.
Despite his regained health, Roy finds himself imprisoned on multiple charges, facing silent threats regarding Rocky’s daughter from his past boss's lawyer. When he finally emerges from prison 20 years later, he lives in Galveston, perpetually haunted by memories of his lost love. Just as Hurricane Ike approaches, Tiffany, now a grown woman, arrives at his door, seeking the truth about her origins. Roy bravely confesses her mother’s tragic story, offering her the closure she desperately needed. As he walks toward the beach, memories of Rocky flood back, intertwining his past with his uncertain future, leaving viewers grieving for the love and losses that defined their lives.
