Octopus Dare is the new computer game at school – everyone is playing it. But only Dinah is any good at it. Soon all she can think about is Octopus Dare. She wins 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.