The second in the series of films about the Lyon family, based on the BBC radio series Life With the Lyons. Ben Lyon appears to have forgotten his wedding anniversary making his wife Bebe furious. When his son sees him dining with a glamorous French singer he thinks the worst. But Ben has laid false evidence in order to surprise the whole family with a trip to France. Only, once in Paris, all the day's previous misunderstandings pail into insignificance at the compromising situations the Lyons get themselves into.

The French Surete and private eye Higgins are after a killer who uses innocent young Americans in a crooked gambling racket, and who sets sail on an ocean liner that also carries inept scoutmaster Freddie Hunter and his troop of boys. Freddie, who's been a "boy scout" too long, has designs on gorgeous Duchess Alexandria. The boys, far better organized than Freddie, are determined to save him from himself. But who will save Freddie from being the killer's next victim?