When a death from his past becomes an obstacle to his chances of competing in the Monaco Grand Prix, Lew Scarsdale decides to hedge his bets by ridding himself of his burden. But doing so brings him under the scrutiny of Supt Johnson.

A girl vanishes mysteriously while on holiday in the French Riviera. The hunt for her is naturally placed in the hands of those sleuths on-the-spot Supt Adam Hunter (Geoffrey Frederick) and Insp. Legrand (Brian Spink).