Craig is a high school student undertaking a 32-hour kissing marathon in front of his school to break a Guinness World Record. He hopes the highly public event will raise awareness of anti-gay violence after a classmate is violently assaulted. At the same time, Craig remains closeted to his own family and secretly hopes the ambitious project will repair his romantic relationship with his ex-boyfriend.

Harry is Craig's openly gay ex-boyfriend who agrees to partner with him for the kissing marathon. Coming from a household with affirming and supportive parents, Harry does not carry the same heavy burden of secrecy as Craig. He participates primarily to support Craig's goals, preferring to keep their connection as a strong friendship rather than reigniting a romance.

The narrators of the story speak as a unified collective of gay men who died during the 1980s AIDS crisis. Watching over the modern teenagers like an audience at an ancient Greek play, they offer historical context and deep empathy. They view the relative freedom of today's youth with a mixture of awe and sorrow, acutely aware of the dangers that still threaten young queer people.

Tariq is a Black, gay high school student whose recent survival of a brutal hate crime serves as the catalyst for the world-record attempt. Despite suffering trauma and lingering fear from his assault, he acts as the primary support system for Craig and Harry. He manages the online livestream and provides encouragement by reciting Walt Whitman's poetry.

Avery is a pink-haired transgender and gay teenager from the town of Marigold. Raised by fiercely supportive parents who affirmed his identity from a young age, he possesses a strong, secure sense of masculinity. He attends a gay prom in a neighboring town hoping to make a genuine romantic connection, though he remains cautious about how strangers perceive his gender history.

Ryan is a blue-haired cisgender teenager who helps organize a gay prom in his small town of Kindling. He hides his sexual orientation from his mother and stepfather, finding his only true refuge with his young aunt. He feels trapped in his hometown and harbors deep anger toward the local boys who constantly bully him.

Neil is a Korean American teenager who frequently worries about his year-long relationship with his boyfriend. His deep insecurities stem largely from his parents, who know he is gay but enforce an unspoken agreement to never discuss it. This familial denial eats away at his self-esteem and makes him prone to jealousy over small interactions.

Peter is Neil's openly gay boyfriend who loves playing fantasy video games. Raised by accepting parents who treat his relationship as perfectly normal, Peter enjoys a healthy level of self-esteem. He cares deeply for Neil but often struggles to understand the intense anxiety his boyfriend experiences.

Cooper is an isolated teenager living in a deeply hostile home environment. After his father discovers his online chats and reacts with homophobic slurs and physical violence, Cooper flees his home. Believing he is unworthy of love, he retreats into dating apps to seek out brief, emotionless encounters to numb his pain.

Caitlin is Ryan's young, supportive aunt. She provides the only safe space in Ryan's life where he is allowed to be entirely himself, regularly letting him visit her home and take her canoe out on the river behind her house.

Julian is a 23-year-old painter who meets Cooper through an online dating application. He treats their meeting as a genuine date, offering respect and affection, completely unaware of Cooper's actual age and desperate emotional state.

Smita is Craig's best friend and a vital member of the logistical support crew for the kissing marathon. While she questions Craig's underlying motives for the event, she provides unwavering practical assistance, making sure the boys are protected from the sun and given water.

Mr. Bellamy is an openly gay teacher at Craig and Harry's high school who arrives to support the boys during their marathon. To the Chorus, he represents a living link to the generation of men who survived the AIDS crisis.

Skylar is an aggressive teenager in Kindling who wields a golf club and uses homophobic slurs to intimidate others. He specifically targets Ryan, seeking to humiliate him in public spaces.