Charley Thompson, a lonely teenager searching for stability, moves with his neglectful father, Ray, to Portland, Oregon. Struggling to fit in at a new school and needing some form of companionship, Charley finds an escape in a local horse racing track. There, he befriends Del, a washed-up horse trainer who offers him a job. The job keeps Charley occupied and introduces him to Lean on Pete, an aging racehorse that Del owns. Charley forms a deep bond with Lean on Pete while being exposed to the harsh realities of the horse racing world through Del and jockey Bonnie. This connection with the horse becomes a rare and precious element of stability in Charley's tumultuous life.

As Ray's erratic behavior escalates and financial strains intensify, Charley's home life deteriorates. Del reveals that Lean on Pete is no longer profitable and may be destined for slaughter, forcing Charley into an emotionally fraught situation. Desperate to protect the horse he loves, Charley makes a drastic decision that propels him into a journey through the unfamiliar American Northwest. Along the way, he navigates physical and emotional hardships in search of security and belonging.