Hoping that she will help hide him, Jonathan Cooper confides in his besotted friend Eve Gill, a novice acting student at the Royal Academy of Dramatic Arts in London, that he is helping famed stage actress Charlotte Inwood, his mistress, cover up the accidental killing of her husband. Jonathan states he is in trouble because Charlotte, who was wearing a blood stained dress, asked Jonathan to retrieve a clean dress for her at her supposedly empty house where he was spotted by the maid, Nellie Goode, just prior to Nellie finding the dead body. Eve agrees to help Jonathan since she is in love with him and believes he is being framed by Charlotte. When the police get involved, Eve tries to find out as much as she can from the lead investigator, Detective Inspector Wilfred Smith, who she ends up calling "Ordinary Smith" at his request, without divulging her connection to Jonathan. With her equally sleuthing father Commodore Gill behind her, Eve, using her acting skills, infiltrates the Inwood household acting as Charlotte's temporary dresser. These dual roles becomes difficult for Eve to manage. In the process of discovering the real killer, Eve ends up falling in love with detective Smith.