Former London constable Nicholas Angel finds it difficult to adapt to his new assignment in the sleepy British village of Sandford. Not only does he miss the excitement of the big city, but he also has a well-meaning oaf for a partner. However, when a series of grisly accidents rocks Sandford, Angel smells something rotten in the idyllic village.

When their beloved school is threatened with closure should the powers that be fail to raise the proper funds, the girls scheme to steal a priceless painting and use the profits to pull St. Trinian's out of the red.