One week before her vaginoplasty, a trans woman named Bree Osbourne, Felicity Huffman, receives an unexpected phone call from a young man named Toby Wilkins, Kevin Zegers, a 17-year-old jailed in New York City. He asks to speak to "Stanley Schupak" (Bree's deadname); Toby claims to be the son of "Stanley." Bree was previously unaware she had a son and, wanting a clean break from her past, nearly renounces him. However, Bree's therapist, Dr. Margaret, refuses to give her approval for Bree's upcoming surgery if Bree does not contact Toby.
Bree flies from Los Angeles to New York City to bail Toby out of jail. Toby is a foul-mouthed runaway who is a small-time drug user and male hustler. Toby’s mother died by suicide when Toby was a child, after which Toby was raised by his stepfather, whom Toby says he does not want to see. Bree pretends to be a Christian missionary and persuades Toby to ride with her back to the West Coast, secretly planning to leave him at his stepfather's house along the way. When they arrive in the town of Callicoon, Kentucky, it turns out that Toby's stepfather was abusive and he molested Toby several times when Toby was a child. Bree and Toby continue driving to Los Angeles together. They also stop by a house in Dallas where a group of transgender women are hosting a gender pride gathering. Later on in the trip, when Bree goes to the restroom, Toby accidentally discovers that Bree has male genitalia. Toby tries to be open-minded but is angry that Bree has not previously informed him that she is transgender.
After their car and money are stolen by a young hitchhiking hippie who calls himself a "peyote shaman," Toby makes some money by prostituting himself to a truck driver, pretending to Bree he got the money from selling drugs. A kindly rancher, Calvin Many Goats, drives Toby and Bree to Bree's parents' house in Phoenix, Arizona. During the drive, Calvin and Bree begin flirting, which disturbs Toby. At Bree's parents' house, Toby and Bree encounter Bree's self-centered mother, Elizabeth; Bree's Jewish father, Murray (who seems to be dominated by Elizabeth); and Bree's rebellious and sarcastic sister, Sydney. Elizabeth disapproves of Bree's transgender identity (it is mentioned that Bree has been estranged from her family for some time), but is astonished to find out she has a grandson. She is kind to Toby and invites him to stay and live with them. Toby enjoys luxury and kindness but hesitates because he does not like his grandparents' disrespectful attitude towards Bree.
Misunderstanding his feelings for Bree, Toby tries to seduce her, saying that he will marry her if she wants. Bree realizes she must tell Toby the truth immediately and reveals she is his biological father. Toby is appalled and infuriated that Bree had not disclosed this earlier. Later that night, Toby steals money and valuable antiques from the house and disappears. Heartbroken, Bree returns to Los Angeles via a plane ticket bought by her parents. Her family finally accepts her calling herself Bree and she has a successful surgery but is unhappy because she feels she will never again see or hear from Toby. While Bree is recovering from surgery, her therapist visits her; after she confesses she made a mistake, Bree sobs on her shoulder.
Months later, Bree is surprised to see Toby at her front door. Bree invites him inside and he tells her that in the meantime he has turned 18, he has bleached his hair blonde, and he has become an adult actor in gay pornographic films in Los Angeles. Bree is also vibrant, happy, and enjoying her job as a waitress at the restaurant where she was formerly a busser. They reconcile, seemingly happy to have each other.
