First an army barracks, then a hospital, and now a school for the third Carry On film.

Ted Ray's headmaster is well-liked at Maudlin Street Secondary Modern and when word goes round that he is intending to apply for the job of headmaster at a brand new school, the children start plotting to make him stay. A visit by school inspectors provides a perfect backdrop for the pupils' bad behaviour designed to render their headmaster unfit for a new job anywhere.

Richard O'Sullivan leads the children's assault on teachers Kenneth Williams, Kenneth Connor, Charles Hawtrey, Hattie Jacques and Joan Sims as Rosalind Knight and Leslie Phillips play the visitors who get caught up in the chaos!