Based on the books by Gillian Cross and adapted for TV by Helen Cresswell, The Demon Headmaster was first broadcast between 1996 and ran for two years. The first series contained six episodes, the second series contained seven episodes, and the third series contained six episodes.
The first three episodes of series one were adapted from the first book, The Demon Headmaster, and episodes 4–6 were adapted from the second book in the series, The Demon Headmaster and the Prime Minister’s Brain.
The second series was named The Demon Headmaster Strikes Again and the third The Demon Headmaster Takes Over – Gillian Cross wrote the storylines for each project, and then wrote the books; Helen Cresswell turned the storylines into screenplays.
In Episode 1 we meet Dinah Glass (Frances Amey), a young girl who moves in with the Hunter family and starts going to the same school as her foster brothers Lloyd (Gunnar Atli Cauthery) and Harvey (Thomas Szekeres). It is not easy, as they seem to hate her, and school is really strange. Pupils suddenly talk like robots and do weird things, even Dinah finds herself acting oddly. She is sure the headmaster has some kind of power over them, and is determined to find out more. But the Demon Headmaster (Terrence Hardiman) is equally determined to stop her.
As the Demon Headmaster’s original plan gets thwarted attention then turns to Octopus Dare. A new computer game that everyone at school is playing…Dinah discovers she is the best at it by far! Soon all she can think about is Octopus Dare. When a competition is announced for the best players of Octopus Dare Dinah goes onto win a place at the grand final, and she is delighted. But there is something strange about it all that scares Dinah – so her friends come with her to the final. Before long they find themselves in trouble, as the Computer Director turns out to be their old enemy, the Demon Headmaster!