A boy who has always believed in the fairness of sport and in the discipline of the martial arts, an evil loan shark who has no respect for anyone, a sordid former policeman who has turned into an organizer of underground fights and a mysterious girl who seems to be made of the same substance of the night. Nightwolf is an action noir movie whose background are the disenchanted atmosphere of a big city's suburbs and the mysterious intricacies of the violence of the nights of the modern gladiators: whether it is for money or for fame, these men will fight in underground arenas, abandoned factories, dungeons lighted by a neon light, where every night the pagan rite of the fighter's glory is celebrated.