Ben is an 18-year-old high school senior in the small town of Trout, Idaho. Shortly after his birthday, a routine sports physical reveals he has a rare, terminal blood disease. Rather than pursuing aggressive treatment, he decides to keep his condition a secret to protect his family and maintain control over his final year. He throws himself into life, joining the football team despite his small build, questioning authority figures, and seeking out new connections.

Cody is Ben's younger brother. As a highly talented football player, he attracts attention for college scholarships and anchors the high school team's success. He works alongside Ben to manage their mother's illness, providing a consistent foundation of loyalty and brotherhood that Ben relies on daily.

Dallas is a smart, athletic student who plays fiercely on the school volleyball team. Though she presents a highly confident exterior and surprises Ben by asking him to the homecoming dance, she carries the heavy weight of early childhood trauma. Her willingness to share her vulnerable history challenges Ben to rethink his own secretive behavior.

Rudy is a local car garage employee who is widely regarded by the Trout community as the town outcast and drunk. Often seen slinking away to a small room off the garage, he lives an isolated life. When Ben begins visiting him and bringing him health supplements, Rudy reveals a surprisingly sharp intellect and a shared appreciation for literature and civil rights history.

Coach Banks is the head football coach and an English elective teacher at Trout High School. He acts as a dedicated mentor to the Wolf brothers, having provided them shelter and support through their mother's difficult episodes for years. He returned to his hometown to coach after his girlfriend died in a car accident, a loss that grounds his coaching philosophy in deep empathy.

Hey-Soos is a specter who visits Ben exclusively in his dreams. Operating as a sounding board and spiritual presence, he listens to Ben's anxieties about life, death, and his hidden illness. He refuses to offer easy answers, instead pushing Ben to examine his own choices, biases, and fears.

Ben and Cody's mother lives with severe bipolar disorder. Her manic and depressive episodes dictate much of the family's home life and routine. Her psychological vulnerability heavily influences Ben's initial decision to hide his terminal diagnosis, as he fears the news will devastate her fragile stability.

Ben and Cody's father is a dedicated parent who works diligently to maintain stability in the Wolf household. He remains committed to his wife despite her severe bipolar episodes, modeling loyalty and quiet endurance for his two sons.

Doc Wagner is the local physician who discovers Ben's rare, chronic blood disease. Though he strongly advocates for aggressive treatment in Denver and pushes for family transparency, he reluctantly agrees to keep Ben's medical secret on the condition that the teenager attends regular therapy sessions.

Marla is Ben's first therapist, tasked with helping him process his terminal diagnosis. She is highly compassionate but struggles deeply with Ben's refusal to pursue treatment or inform his family, eventually leading to professional friction between them.

Mr. Lambeer is a conservative civics and government teacher whose traditional curriculum Ben frequently targets. Frustrated by Ben's rebellious references to historical texts and progressive ideas, Lambeer clashes heavily with him over classroom authority and grades.

Boomer is a former football teammate of Coach Banks and the father of Sooner Cowan. He is infamous in Trout for his volatile behavior and struggles with alcohol, which frequently cause physical and emotional tension for his son and the local team.

Sooner is a strong player on the Trout Cougars football team. He faces significant difficulties stemming from his father's violent nature, suffering injuries at home. He causes major conflict on the team when he makes a racist remark during an important game against Timberline High School.

Joe Henry is a four-year-old boy living in Dallas Suzuki's household. Ben grows fond of him and often joins in his games when visiting Dallas, enjoying the boy's energetic presence and observing Dallas's deep devotion to him.

Sylvia is a student at Trout High School who strongly opposes Ben's progressive viewpoints. She gets into a heated debate with Ben over *The Autobiography of Malcolm X*, arguing that the book should be burned, which prompts Coach Banks to intervene with a dramatic lesson.

Mr. Phelps is the principal of Trout High School. He attempts to mediate the ongoing, heated disputes between Ben and Mr. Lambeer, formally warning Ben that his academic rebellion could jeopardize his high school diploma.

Alex is Ben's second therapist. Unlike Marla's emotional approach, Alex is immediately confrontational regarding Ben's choice to refuse medical treatment, threatening to report him for endangering himself and causing immediate friction.