After his doctor informs him he will die in six months, Professor Henry Todhunter (Thomas Mitchell) decides to spend his last days killing someone who contributes nothing but harm to society. When Henry learns that his friend Betty's (Geraldine Fitzgerald) husband, Michael (Jeffrey Lynn), has been painting forgeries of ancient paintings for gallery owner Ketti Moret (Mona Maris), he investigates the fraudulent dealer's life. Judging that Ketti is truly evil, Henry prepares to murder her.