Dancing instructors Laurel and Hardy accept a phoney insurance deal from two gangsters posing as insurance salesman. At the same time, Grant Lawrence, a young inventor is working on creating a new invisible ray machine that will revolutionize jungle warfare for World War II. Trudy Harlan, Grant's lover and one of Stan's dancing pupils, invites Grant and the boys to her house for tea when her parents are away. Trudy's father Wentworth Harlan almost discovers Stan and Ollie when he returns home but finds Grant and angrily confronts him. Grant is ordered to leave and never talk to Trudy again, whilst the boys narrowly escape being found by Trudy's parents once again.