In the film, 18-year-old Noah moves from Florida to London with her mother, Ella, to live with her new wealthy stepfather William and her stepbrother, Nick. She bids farewell to her best friend Haley and her boyfriend Dan, gifting them her car as a parting gift. The move is not something Noah is entirely excited about, especially because she is wary of her relationship with her new stepbrother, who she initially perceives as the "golden boy" and somewhat entitled.
Upon arriving at the grand house, Noah is introduced to her new surroundings, including her spacious bedroom, and she quickly observes Nick from a window getting out of the pool, which sparks their mutual dislike. She also encounters other family members and learns more about Nick's personality, discovering that he has his own way of earning money through an app, which challenges her assumption that he is spoiled. During their interactions, she meets Anna, a girl close to Nick, and gets an insight into his social circle, including his close friend Lion.
The story takes a tense turn when Noah and Nick attend an event, where Noah becomes suspicious of Nick's relationship with Anna and notices Nick's interest in racing cars. This curiosity leads her to ask Nick about his hobbies, and she proves her knowledge of cars, impressing him in the process. Their bond deepens when she receives a distressing photo of Haley and Dan kissing, making her upset. Outraged, Noah demands that Nick take her to find Haley, which leads to a high-energy car racing event. During the race, Noah shows her skill behind the wheel, winning despite attempts by Ronnie, a dangerous racer, to sabotage her.
As their relationship develops, Noah learns more about Nick’s fighting skills and his involvement in dangerous races. One such race results in Noah taking Nick's place against Ronnie, a ruthless opponent, and she surprisingly wins. However, this victory intensifies the danger when Nick has to fight Ronnie in person. Their fight escalates, leading to Noah experiencing a panic attack, revealing her struggles with violence, darkness, and small spaces stemming from her traumatic past—specifically past abuse involving her father.
Further revelations come when Noah discovers that Maddie, who is Nick's sister, is her half-sister, and that Nick’s mother—who has been sober—left him and William to recover from her own struggles. She also finds out that Anna isn't actually Nick's girlfriend. Despite these revelations, Noah and Nick share several tender moments, including a kiss, as their bond grows stronger.
Meanwhile, tensions rise when Ella invites Dan over, unaware of his cheating with Haley. This confrontation reveals Dan’s attempts to win Noah back, which she rejects, reaffirming her feelings for Nick. In a humorous yet intense scene, Nick offers to pay Dan to leave, and they part ways with a punch thrown in jest about Dan’s cheapness.
Their relationship faces further challenges when Nick attends a fight with Ronnie, which Noah leaves due to the violence and her concern for Maddie. Ronnie threatens Nick and steals his car, prompting a series of dangerous events, including a narrow escape at a petrol station when Ronnie attacks their vehicle. Lion urges Nick to fight Ronnie to protect himself—highlighting the increasing danger. However, Nick's protective instincts lead to a conflict with Noah when she is harassed at a bar, causing an argument and a temporary break in their relationship. Later, at a party, Jenna and her friends lock Noah in a cupboard, triggering flashbacks and panic attacks due to her traumatic history with her father who once tried to kill her.
In a moment of vulnerability, Noah shares her past with Nick, and their connection deepens when they have sex, offering her comfort. The plot thickens as Ronnie violently attacks Lion, and it is revealed that Noah's father, recently out of jail, is involved in a scheme with Ronnie to locate Noah. They eventually kidnap her, demanding ransom, leading Nick to rush to her rescue. During a confrontation, Nick is stabbed, but Noah manages to escape her father’s grip and drives away, wounded but determined. A tense car chase ensues, ending with Nick causing a crash to stop her father, who is holding Noah at gunpoint. Police arrives just in time, and Noah, bruised and shaken, tends to an unconscious Nick.
Six weeks later, both Noah and Nick have recovered physically and emotionally. Their bond remains strong, though William and Ella momentarily consider whether Noah and Nick might have romantic feelings for each other but dismiss the idea. The film concludes with a touching scene of Noah and Nick sharing a kiss underwater, symbolizing their enduring connection and hope for the future.
