Penelope Shawn is a very pretty, very appealing young girl who has a most unusual profession; she's a burglar. Burglary is part of her family's tradition. When David Warren finds her attempting to rob his apartment, he decides it's up to him to reform her. Penelope, who finds David most attractive, is more than willing to be reformed by him, but his fiancee, Helen Chandler, is not particularly enthusiastic about the idea. Nor is Penelope's father, who is aghast at the way David has shaken Penelope's faith in the ideals and traditions of her family. Meanwhile, Penelope has hidden in David's apartment the jewels she had stolen from his neighbors, and the police are on David's trail, thinking he was an accomplice. His mother, Lady Warren, and his rich uncle, Sir George, become involved. Sir George decides David should marry Penelope, but her father, Henry Shawn, considers David not good enough for the daughter of a long line of first-class burglars. Meantime the police are blundering in and out of David's apartment in a hunt for the stolen jewels, which finally turn up in the police sergeant's pocket—put there by Penelope. After disposing of the jewels thus satisfactorily, Penelope manages also to dispose of Helen, and by this time she has convinced David that he really must marry her and see that she continues in the path of an honest life.
Produced successfully in London.