Its basically the young man seeking revenge redeemed by love plot mixed in with the old cop with a guilty conscience who wants to atone for his sins plot. And its not half bad with some nice motorbike stunts, cool sunglasses worn by Mitchum and nice location photography in Spain. And of course there is that ambience found in these 70s Euro action films where there are long pauses, meaningful angles as well as a gallery of existential or thoughtful characters. Its no classic but its fun.
