Peter Marshall (Fred MacMurray), who works for the Trotter Poll ("like the Gallup Poll, but not as fast"), is sent out to find a missing co-worker, Hector Smedley. He goes to see the last family the man was supposed to interview, the nutty and murderous Fleagles. There he runs afoul of Mert and Bert Fleagle (both played by Peter Whitney), the gun-toting twin sons of Mamie Fleagle Smithers Johnson (Marjorie Main).