The Lonely Ace follows Ren Aoyama, a famous high school volleyball setter admired for his beauty, talent, and perfection. Despite being loved by everyone around him, Ren secretly struggles with loneliness, emotional exhaustion, and the pressure of constantly meeting others' expectations. His only true companion is Kiba, a mysterious black wolf only he can see, who has stayed beside him since childhood and quietly supports him through his darkest moments.