An original comedy written and directed by Claudia Wilson, Diamond Girl tells the story of Margaret, the estranged wife of Carl. When Margaret passes away, her last wish is to be cremated and have her ashes turned into a diamond. Carl's lifelong friend Patrick convinces Carl to give the diamond to his long-waiting girlfriend Marjorie. Once Marjorie has the ring on her finger, she begins to develop strange personality quirks, leading Carl to believe the ring is possessed by his late wife. Carl, not wanting to tell his fiancée that she is wearing his dead wife's ashes, consults her spiritualist (Madame Cleo) for answers. A seance is held and Carl is left to make a decision about the ring and his future with Marjorie.