Marko Stemper, 19 years old, comes from a disadvantaged background and works as a window cleaner. His father, an alcoholic, tyrannizes the whole family, so Marko's only joy in life is boxing. As he is the most promising talent in his club, Gerd Hermsbach, a local demimonde boss, offers him the opportunity to become a professional. Marko accepts, but has to pay a high price...