When a confused eyewitness identifies New York City cabbie Brick Tennant as a killer, he is sentenced to death for a murder that he wasn't involved in. Though no one is willing to listen to the innocent prisoner's pleas for freedom, Brick's faithful fiancée, Mary, knows that her lover is innocent because she was with him when the crime was committed. As the scheduled execution draws ever nearer, Mary begins to investigate the murder herself.

A writer takes a job as a secretary because her scrupulous husband isn't bringing in the dough as an attorney. When her new employer is murdered, she can't seem to make up her mind as to whether she "dunnit" or not.