Murder, He Says 1945

Pete Marshall Fred MacMurray is sent out by the Trotter Poll company to track down a missing coworker, Hector Smedley, and ends up at the home of the dangerous Fleagle clan. There he runs afoul of Mert Peter Whitney and Bert Peter Whitney, the gun-toting twin sons of Mamie Fleagle Smithers Johnson [Marjorie Main].

Mamie insists that Pete pretend to be Bonnie Fleagle’s boyfriend to win the confidence of her dying grandmother, Grandma Fleagle Mabel Paige. Grandma has hidden $70,000 stolen by Bonnie and her father, but refuses to reveal the whereabouts because she claims she has been poisoned by them. Before she dies, she teaches Pete a nonsensical song that also connects to Elany Fleagle [Jean Heather], Mamie’s not-so-bright daughter.

As the truth unfolds, the Fleagles capture Pete, and a woman claiming to be Bonnie appears. She’s actually Claire Matthews [Helen Walker], whose innocent father was maligned by Bonnie’s father in a bank robbery. Pete longs to escape, but Claire insists on staying so they can retrieve the money and clear her father’s name.

During a tense dinner, the Fleagles plot to poison Claire, but Pete discovers that all but one plate are laced with poison; the only safe dish belongs to Mr. Johnson [Porter Hall], Mamie’s third husband. Johnson slips away but is later found glowing and dead. Yet it’s revealed he had faked his death, complicating the chase.

Bonnie Fleagle [Barbara Pepper] breaks out of prison and returns for the loot. She helps Pete decipher the cryptic song and its clues, guiding Claire to a key that opens a safety deposit box. Now the chase is on as the entire Fleagle clan, including the faked-dead Mr. Johnson, pursues Pete and Claire through the house’s hidden passageways. In a final dash, the couple uses the secret corridors to drop each pursuer into a hay baling machine, escaping to safety.