Based on the 1920s Thompson-Bywaters criminal case. Fanciful Edith (Little) makes a grave mistake by marrying staid Percy Thompson (Moran), whom she soon feels is dull, resentful, and cold. When Edith re-connects with exciting family friend Frederick Bywaters (Gruffudd), she strays, eventually confessing to Freddy that she wishes Percy were dead. He soon is and the adulterers stand trial for his murder.