Henry wins the prize of being headmaster for a day. At first, he is popular with his fellow pupils, but Miss Battle-Axe, Margaret and Peter hatch a cunning plan to get rid of him.
In an effort to avoid having the play the role himself, Henry persuades Anxious Andrew to audition for the King of the Fairies role in the school's play.
Peter's well on the way to winning the school talent contest with his rendition of 'Frere Jacques', ably assisted by his uber manager Horrid Henry. But when Moody Margaret decides she wants a piece of action she turns svengali in a ruthless display of ambition.
Henry has drawn a rude poster which has been entered into a school competition. Now, he has no choice but to plan a heist with Margaret to get it back before it's revealed.
The local ice-cream man is going out of business as more and more people turn to healthy foods. Henry is not happy, but after a visit to the ice-cream factory, he comes up with the solution by accident.
Ashton Primary are introducing a school uniform, starting of with blazers. As the blazers make everyone look alike, Henry and Ralph use this to their advantage to raid the confiscation cupboard. .
Will Moody Margaret and Sour Susan stop at nothing to make sure that Henry doesn't get what he's always dreamt of? Henry's about to find out that sometimes it is possible to beat a cheat, and sometimes it isn't.
Sometimes it seems as though Henry has to fight his battles all on his own, though when it comes to sharing the spoils, that doesn't seem to matter so much.
A wind turbine is installed to help Henry's family save money on electricity bills, but when there's no wind, there's no power so Henry has to come up with a cunning plan.
Mum's cookies are a big hit with everyone, including Henry. Now he's just got to figure out how to keep the supplies coming, but Peter wants to be in on the act too.
When Moody Margaret becomes editor of the school newspaper and Peter becomes knitting editor Henry knows there a scoop to be had, he just can't figure out where it is.
When Dad announces that his new job means they're going to have to move house, Henry decides to counter campaign, with not quite the result he was hoping for.
