Alicia Huberman (Ingrid Bergman) is a woman with a notoriously promiscuous past. The American daughter of a convicted Nazi spy, she is recruited by agent T.R. Devlin (Cary Grant) to try and sneak into the ranks of escaped Nazis now residing in Brazil. Reluctant at first, she finally agrees. Alicia and Devlin fall in love on the mission, but their relationship gets further complicated when his superiors order Devlin to have Alicia seduce Alex Sebastian, one of her father’s friends, as well as one of the key figures within the ranks of the exiled Nazis in Brazil. Alicia is torn between duty and love when Sebastian proposes, but she marries him after Devlin coldly tells her to do whatever she wants. Thanks to her marriage with Sebastian, Alicia now has access to new information. She concludes that her husband has something in the cellar that he doesn’t want even her to know about, and informs Devlin about it. He talks her into throwing a big party at her husband’s house so he could freely inspect the cellar. In it they find uranium ore hidden in vine bottles. Sebastian realizes that Alicia had stolen the key to the cellar, and decides to poison her. Alicia realizes what her husband has done to her, and Devlin comes to the rescue, leaving Sebastian at the mercy of his disgruntled Nazi peers.