Best friends Nikki and Deja face a dilemma when some of their class take advantage of an inexperienced young teacher sent to cover for their regular teacher who has broken an ankle. When fellow classmates dare to behave in ways that would not normally be tolerated, the kind-hearted pair decide to intervene but an attempt to prevent a mean trick backfires. The class soon regret their antics when Mr Willow is replaced by Mr Blaggart, a fierce disciplinarian with an uncanny ability to spot the slightest infraction of his many rules. The girls are equally dismayed by this reversal of their situation and ponder whether they can find a solution. This series with its well-realised characters, presents a funny and very recognisable picture of school life, black and white illustrations adding to the humour of the story told.