 The post's commander, Colonel Bloodnok (Sellers), has been assigned for security purposes a supposed "daughter" (Carole Carr) who is actually a female MI5 operative.Harry soon becomes smitten with the "daughter", and they work together to foil an attempt by the secret agents to purloin Professor Purehart's formula.National Service in Britain in the 1950s obliged all fit British men to serve in the military for two years, and thereafter three and a half years in the reserves.