私家侦探
Private investigator Tom Welles is contacted by Daniel Longdale, attorney for wealthy widow Mrs. Christian, whose husband has recently died. While clearing out her late husband's safe, she and Longdale find an 8mm movie which appears to depict a real murder of a girl, but Mrs. Christian wants to know for certain. Welles is compelled by both Longdale and Mrs. Christian not to reproduce the film in any way, and that only they need to know about the investigation.