Jon thought being seven and a half kilometres from Earth would save him from his teacher, Mrs Hall, but apparently not. Now that the President of Pluto is on his honeymoon, Mrs Hall has been chosen to look after Pluto. But when her new laws mean everyone is sat around doing spelling tests and Iron Age projects, Jon and Straxi must take matters into their own hands .... especially when there's a giant, mutant snarlger on the loose!