DEAD RINGER

For eighteen years, identical twin sisters Margaret and Edith have been estranged from each other. It started when Margaret faked a pregnancy to "steal" Edith's fiancé, Francesco "Frank" DeLorca, a rich American military officer both sisters dated during World War II. They meet at the funeral of Frank, whom both sisters mourn. Margaret will be secure for the rest of her life thanks to her husband's wealth, but Edith's prospects are dismal. Her business, a cocktail lounge, is losing money, and she is threatened with eviction for not paying her bills. Edith plans revenge against Margaret, phoning her to come to her room above the lounge so that they might settle their score. Soon after Margaret arrives, Edith shoots her, then swaps clothes with the corpse, framing Margaret's murder as her own suicide. She then takes over the DeLorca mansion by assuming Margaret's identity. But the mansion's servants start to become suspicious.

For one thing, the house's Great Dane, known for hating Margaret, befriends Edith. Second, Edith is a smoker, something Margaret was adamantly against. Meanwhile, Jim, a police detective who had been seeing Edith steadily before her "suicide", visits the fake Margaret several times, asking questions. Edith's scheme runs into trouble when Margaret's lover Tony unexpectedly shows up and quickly sees through her charade. Tony blackmails Edith over the killing of Margaret, receiving expensive jewelry as payment. But after Edith discovers that Margaret and Tony had conspired to murder Frank by poisoning him, Tony and Edith quarrel; when he threatens her, Margaret's Great Dane attacks and kills him.

Already suspicious about DeLorca's death, Jim leads a police investigation, exhuming Frank's body and later finding traces of arsenic. When Jim arrives to arrest "Margaret", Edith confesses her true identity, but Jim refuses to believe her, telling her, "Edie would never hurt a fly". Retaining her pose as Margaret, Edith is tried, convicted of murder and sentenced to death. As she is taken from the courthouse, Jim approaches her and asks if she really is Edith. She denies it, reminding him that he said, "Edith would never hurt a fly". She then departs for her appointment with the gas chamber.

Edith is exposed, convicted of murder, and sentenced to death as Margaret, maintaining her assumed identity to the end.

The ending underscores the tragic irony of Edith's plan: her desperate gambit to claim her sister's life leads not to wealth or closure, but to ruin. By refusing to break character even at the last moment, Edith seals her fate, highlighting themes of mistaken identity and the blindness of justice. The closing exchange with Jim drives home her isolation—she is punished for a crime she committed, yet in the eyes of the world, the wrong sister is sent to her death.