Daughter of a small town police lieutenant, Mary MacLaren tells her story while on the witness stand for drunkenness and attempted suicide. Mary's friend Helen, the daughter of the police captain, persuades Mary to do things against her better judgment. After Mary inadvertently sips spiked punch, she puts the house key in her coat pocket and then loans the coat to a friend who decides to get married at once. The coat is not returned, and without her key, Mary stays out all night. She is caught by the police, led by her father, in a hotel room with a man. Finally, Mary manages to unravel the chain of circumstantial evidence that had threatened her good reputation.