Marla Bernstein is a pretty, dark-haired teenager who happens to be the ward of Ben Morningstar—a semi-retired mobster. When Marla suddenly disappears, the gang boss is forced to call in private eye Amos Walker. Unfortunately, the only clue to Marla's whereabouts is a pornographic photograph that clearly proves that she's become part of a world that disgusts even her criminal guardian. The photo leads Walker into the dark world of Detroit's porn shops and blue movies, where Marla's trail becomes murkier and even more dangerous to follow. As first cases go, Walker could have certainly asked for one less challenging.