When Chuck Williams goes into a Chicago café to meet his girl friend, Helen Walker, he happens upons a gangland murder and runs from the killers, who know that he can identify them. Penniless, Chuck ends up at his aunt and uncle's countryside "Happy Hunting" lodge. The Williamses, Joe and Martha, are just about to leave for their annual St. Louis winter vacation, and have closed up the lodge, but are intimidated by Chuck, whom they have always regarded as a criminal. With his usual surly manner, Chuck demands that they bring him food, and menacingly jabs a knife into the hunk of meat they bring out. Later, the Williamses' employee, Julie, goes into the lodge when she sees smoke coming out of the chimney. Julie is surprised to meet Chuck, as the Williamses never mentioned having a nephew, but he says that he is keeping the lodge open for the winter and is her boss until his aunt and uncle return. Julie agrees to continue working, although Chuck declines to give her the key to the cellar, where the wine and food are stored. That night, Julie awakens to a thudding noise and finds Chuck in the cellar, claiming that he was making sure he closed a wine barrel spigot. The next day, two strangers check in, saying that they are expecting a third guest from San Francisco. Julie, suspicious of the men because they ask a lot of questions, tells them that she is Chuck's wife. When Chuck goes into town, real estate agent George Nadroy asks him for the Williamses' vacation address, as they have been interested in some property that is now for sale. Chuck does not have their vacation address, so George gets it from the mailman. Some time later, however, when George's letter is returned, he confronts Chuck while he is hunting. George refuses to accept Chuck's assertion that he has no additional information regarding his relatives' whereabouts, but is frightened by Chuck's menacing manner. As George leaves the woods, he narrowly escapes being killed by falling boulders, and reports to Sheriff Dave Lawson that Chuck tried to kill him. At a carnival, Dave tells Chuck about his conversation with George, and Chuck appears surprised to hear about the boulders. Helen then surprises Chuck with a visit to the carnival, but when he realizes that Helen has tipped off the gangsters, he leaves her and returns to the lodge. George, meanwhile, has gone to St. Louis and learned that the Williamses never arrived, nor made their regular bank deposit. Alarmed, George returns home with the news, and Dave tells Julie to keep an eye on Chuck. Feeling protective of Chuck, with whom she has fallen in love, Julie borrows a friend's car and drives to St. Louis, where she mails a fake postcard, signing his aunt and uncle's names. That night, Julie lies to Chuck about where she was, and he forcibly takes her to the lake, ostensibly for night fishing. Julie, who cannot swim, is now frightened of Chuck, and they both fall into the water when Chuck rocks the boat. Chuck rescues the drowning Julie, and they confess their love for each other. George's fears that Chuck may have killed the Williamses for an inheritance finally prompts Dave to consider arresting Chuck, but he cancels his plans when Julie's fake postcard arrives. While Chuck is out fishing, Julie steals the cellar key and finds an axe suspiciously placed near the wine barrels. Chuck returns from fishing and shows surprise that his "tightwad" aunt spent money on a postcard. The mysterious guests, who are really part of the gang that commited the murder, learn from the barber that Julie and Chuck are not married, and race back to the lodge to kill Chuck, who is hunting in the woods. Chuck is unharmed, but wounds the two men when he returns their fire. As the sheriff arrives with a posse, Chuck and Julie hide in the cellar. The posse begins to burst through the cellar door when Joe and Martha return from their trip. Joe excitedly tells Chuck that on his suggestion, they vacationed in New York instead of St. Louis for the first time in twenty years. Realizing his mistake, George slips out quietly. Chuck then admits to Dave that the two men were trying to kill him because he witnessed one of their mob killings.