The first in the long-running comedy series chronicles the misadventures of Sergeant Grimshawe (Hartnett) and his latest batch of recruits doing their National Service. Grimshawe is due to retire and wants to leave a success so he takes the bet of rival Sgt. O'Brien (Scott) that he will have the championship platoon. Then he meets the bumblers he must whip into shape. Based on the book "The Bull Boys" by R.F. Delderfield. The title was deliberately used to cash in on the success of 1957's "Carry On Admiral," which had nothing to do with the subsequent films.