Noah is a 17-year-old high school senior who recently relocated from Canada to California. Struggling to adapt to her wealthy new environment, she misses her friends and her life back home. She is fiercely independent, enjoys car racing, and possesses a guarded nature shaped by past trauma.

Nick is a 21-year-old law student who lives a double life, balancing his father's strict expectations with an underground world of street racing and fighting. He harbors resentment toward his parents' choices and uses a tough, playboy exterior to keep others at a distance. He feels intensely protective of his younger sister and struggles with his confusing reactions to his new stepsister.

Raffaella is Noah's mother and William's new wife. Hoping for a fresh start after a difficult past, she tries hard to integrate Noah into their luxurious new lifestyle in California. She is caring and deeply invested in her daughter's happiness, though she sometimes misses Noah's internal struggles.

Ronnie is a rival connected to the underground street racing and gang scene in Los Angeles. He holds a bitter grudge against Nick and becomes deeply antagonistic toward Noah after she humiliates him by beating him in a street race.

Noah's estranged father is a former NASCAR driver with a severe alcohol use disorder. His violent history casts a long shadow over Noah and Raffaella's lives, serving as the root cause of Noah's deep-seated trauma.

William is a wealthy, successful lawyer and Nick's father. He attempts to create a unified blended family with Raffaella and Noah by providing them with extravagant comforts. He holds strict expectations for Nick, requiring him to focus on law school and abandon his reckless habits.

Jenna is a longtime member of Nick's social circle who quickly befriends Noah. She acts as a bridge between Noah and the intimidating Los Angeles party scene, offering companionship, humor, and practical advice.

Dan is Noah's boyfriend from Canada. He represents the comfortable, familiar life Noah left behind, but his selfish actions quickly complicate her transition to Los Angeles and sever her ties to her past.

Lion is one of Nick's closest confidants and a former roommate from when Nick lived away from his father's house. He provides Nick with a sense of brotherhood and acts as a grounding presence, occasionally warning Nick to be careful with his impulsive choices.

Beth is Noah's best friend from Toronto. Initially a source of long-distance comfort, Beth's choices fundamentally alter Noah's connection to her Canadian roots and push Noah to find belonging in her new environment.

Mario is a bartender and acquaintance of Nick's who befriends Noah. He provides Noah with a social connection outside of the Leister household and helps her secure a job, acting as a friendly alternative to the drama in her life.

Madison is Nick's five-year-old half-sister who lives in Las Vegas. She has diabetes and requires careful attention. She represents one of the few pure, healthy connections in Nick's life, bringing out his compassionate qualities.

Anne is Nick and Madison's mother. Her decision to leave William and young Nick for another wealthy man severely traumatized Nick and damaged his ability to trust women.

Anna is a girl involved in Nick's casual party scene. She frequently hooks up with Nick and harbors jealousy toward Noah as Nick's attention begins to shift toward his new stepsister.

Thor is Nick's pet dog. Despite Nick's initial threats that the dog is dangerous, Thor quickly proves to be friendly and welcoming toward Noah.

Zack is a young man who attends the same underground parties as Nick. He appears helpful at first by giving Noah a ride, but his true intentions surface when he secretly spikes her drink at the party.