At a party, Carl and his wife, Annette, are talking with a mutual friend, Lorna - an attractive and charming woman - who is moving to San Francisco. She wants Carl and Annette to care for her dog. Shortly thereafter, Annette has Perry over for lunch. While they're dining, Carl grips his stomach in evident pain. Later, he goes to the doctor at Annette's insistence, but Carl writes it off as the results of rich food. Days later, Carl gets a call from the doctor, telling him that he needs to see him right away. The doctor swings by the house and tells Carl that he'd like to see him alone, away from Annette. The doctor informs Carl that traces of arsenic was discovered in his medical tests. Carl refuses to believe that Annette would do such a thing and orders the doctor out of his house. Annette suggests that the two of them take a trip to their vacation cabin in the mountains, and Carl readily agrees. The next morning, as Annette prepares coffee for the two of them, Carl loads the car. As he comes back inside the house, Annette puts sugar in her coffee, then keels over on the floor. The same doctor informs Carl that Annette has has arsenic in her system and must have died from it. The doctor concludes that Annette must have poisoned herself by mistake, intending to murder Carl. In the final scene, Carl is in a car with Lorna, his girlfriend. He reveals to her how close he came to dying while swalloing the first dose of arsenic to throw the doctor off the trail of his wife's murder.