With a flu epidemic running rife, three new bumbling recruits (Kenneth Connor, Kenneth Williams and Leslie Phillips) are assigned to Inspector Mills' police station. With help from Special Constable Gorse, they manage to wreck the operations of the police force and let plenty of criminals get away, even before they arrive at the station. They all have to prove themselves, or they'll be out of a job and Sergeant Wilkins will be transferred. Sub-plots include romances between sergeants Wilkins and Moon and constables Constable and Passworthy.