When James is kidnapped by aliens, he can't believe his luck. They want to transform his feeble human body, and James can have whatever superpowers he likes. He chooses super-speed, super-brains, and super-strength. But James soon starts to realise he might have gotten slightly more than he asked for.
My 6 year old spends much of his time pretending to some sort of superhero or the other. This book was great fun as it points out some of the drawbacks of being "super" e.g. being so strong that the door explodes when you slam it.