Frank Johnson (Ross Elliott
), a window-dresser and struggling artist, accidentally witnesses a mob-related rub-out of a witness (Thomas P. Dillon
), while out walking his dog one night -- after being shot at for his trouble, he's approached by the police, who want to put him into protective custody. But before they can do that, he runs out, and it's up to Inspector Ferris (Robert Keith
) to find him before the killer does. He approaches Johnson's wife, Eleanor (Ann Sheridan
), only to discover that not only were they the most distant -- nearly estranged -- couple he's ever encountered, but that she doesn't want to help find him, or care if he is found. Then she learns that he has a potentially serious heart condition that he never told her about, and that he has no medication -- she decides to try and find him to give him help, dodging the police with help from a pushy reporter named Leggett (Dennis O'Keefe
), covering his job and all of his old haunts; and in the process, she discovers a man that she never really bothered to know or understand, one who not only wanted to love her but does love her, despite the way their marriage has gone, and discovers that there may still be a marriage worth saving. But to do that she's got to find him to head off not only a potentially fatal heart seizure but also save him from the killer who, unbeknownst to her, is just a step behind her and has already started covering her trail and murdering potential witnesses.