Captain Underpants and the Revolting Revenge of the Radioactive Robo-Boxers

About this book

When we last saw George and Harold, they had been turned into evil zombie nerds. But why didn't Captain Underpants save them from this fate? Because Tippy Tinkletrousers and his time-travelling hijinks prevented George and Harold from creating Captain Underpants in the first place! Could this be the…