Circuit angel is a story about the young and tough girl Mariko and her friends. One weekend while they are out riding their motorcycles, a mysterious rider on a blue bike shows up and races them down the mountain. Mariko's childhood friend Keiichi ends up being hurt and hospitalized, so Mariko takes it upon herself to get both justice and revenge by challenging the blue biker to a race. A real race, on a real track, with real racing motorcycles.