Riley is a 16-year-old high school student and the child of a prominent congressman. Being gender fluid, Riley experiences dysphoria and anxiety, constantly trying to manage societal expectations by dressing as ambiguously as possible. To cope with their isolation and the pressures of starting at a public school, Riley starts an anonymous blog to express their true feelings and connect with others.

Sean is Riley's father and an incumbent congressman currently running for reelection. He is highly focused on his political career and public image, which creates distance and tension in his relationship with his child. Despite his demanding schedule and occasional quick temper, he tries to bond with Riley over shared interests like classic rock music.

Sharon is a schoolteacher and Riley's mother. She is supportive and concerned about Riley's mental health, especially following Riley's recent stay at an inpatient psychiatric facility. She often attempts to mediate the tension between Riley and Sean, trying to encourage Riley to make friends and adjust to their new school.

Jason is a student at Park Hills High who plays on the football team. He has faced bullying in the past for his weight and interests, leading him to try and blend in with the popular crowd to protect himself. He befriends Riley early on, though he struggles to balance this friendship with his desire to maintain his social standing on the football team.

Bec is a confident, somewhat mysterious student at Park Hills High who plays guitar in a band called Fluorescent Sunburn. She has a distinctive, androgynous style and is unafraid of standing out. She quickly forms a connection with Riley, offering them a non-judgmental space and introducing them to an LGBTQ support group in Los Angeles.

Jim is a star running back on the Park Hills High football team. He is aggressive and highly conscious of his status, remaining openly hostile toward anyone who does not fit his narrow worldview. He immediately targets Riley for their ambiguous gender presentation, using slurs and physical intimidation to assert dominance.

Sierra is Jim Vickers's girlfriend and part of the popular elite at Park Hills High. She is openly disdainful of Riley, frequently making cruel remarks about their appearance. Despite her harsh exterior, she deals with her own personal struggles, including a highly critical mother who publicly belittles her.

Doctor Ann is Riley's psychiatrist, providing a safe and confidential space for Riley to discuss their anxiety and gender dysphoria. She encourages Riley to find a cause they are passionate about and provides practical coping mechanisms to manage their panic attacks.

Erik is Bec's brother, who spends much of his time working out and trying to secure a spot on the high school football team. He is willing to do favors for the popular athletes in hopes of gaining their approval and increasing his social standing.

Mike/Michelle is a leader at the Q, an LGBTQ support group, and works for QueerAlliance. She is welcoming and perceptive, identifying the positive impact Riley's writing has on the community and encouraging Riley to become more actively involved in advocacy.

Andie is a transgender girl who discovers Riley's blog. She reaches out to Riley during a moment of extreme distress after coming out to her family goes poorly. Her interaction with Riley highlights the real-world impact of the online community.

Casey is a student in Riley's French class. They practice French together, representing one of the few positive daily interactions Riley has at Park Hills High. Casey is quietly undergoing personal growth and finding his own courage.

Kanada is a transgender woman and a regular attendee at the Q. She is warm and welcoming, helping Riley feel more comfortable during their first visit to the support group.

Elias is the head of security for Sean Cavanaugh. He manages the logistics and safety of the congressman's family, acting as a buffer between the Cavanaughs and the public.