The central mystery of the missing $250,000 is resolved when Reggie realizes that the seemingly worthless items in her late husband's travel bag hold the key. The fortune was converted into three immensely valuable rare stamps (including the famous Gazette Maldave), which were affixed to a plain envelope hidden in plain sight.
The film's major twist is the true identity of the villain. The supposed CIA administrator Hamilton Bartholomew is revealed to be Carson Dyle, the fourth member of the WWII OSS squad who was thought to have been killed in a German ambush. He orchestrated the entire scheme to steal the money for himself. In a tense climax at an empty theatre, Reggie is saved by Cary Grant's character, who utilizes a stage trapdoor to send Dyle to his death. Grant's character finally reveals his true, lasting identity: Brian Cruikshank, a legitimate U.S. Treasury agent.