The Star Runner of the title is a beautiful but dangerous horse. Travis, a teenage budding writer from New York, has a fierce temper. While in New York, he was disciplined for physically attacking his step-father, who was burning Travis’ writing. After a stay in juvenile detection, he goes to stay with his uncle, Ken, on Ken’s ranch in Oklahoma. There he becomes friends with Casey, a girl who teaches riding on the ranch, trains horses, and is a competitive rider. Star Runner is a problem horse that she is struggling to train.
Travis is still at loose ends as he resists the necessary discipline to work effectively on the ranch. Travis maintains his passion for writing, however, and does persevere with completing a book manuscript. He is confused about his feelings toward Casey, who resists getting involved with him in part because of their age and also his behavior issues. His anger continues to manifest, especially as related to his feelings about his writing, as he throws things at his uncle and endangers Ken’s young son. When his friend Joe from back home arrives and ends up in big trouble by killing someone, Travis realizes how serious a situation can turn. By the end, Travis seems to have resolved many of his issues, but the parallel between him and the horse ultimately dissolves: the horse apparently dies, but Travis survives with, it is suggested, a bright future; he may become a “star.”