It is 1947, and many boarding schools who were evacuated during the war are returning to their premises. Hilary Hall (boys) are back in their old school buildings after five years and are just settling in when they receive the news that they will have to share their premises with a school of similar size and type. Unfortunately, ‘The Ministry’ has got its blue and pink cards mixed up and St Swithins (girls) arrive en masse. Confusion and chaos reign among teachers and pupils alike – and Rainbow the caretaker is none too pleased either!