Aaaggghh! / Overdue

S1 E101: Harry has a nightmare in which he is chased by a monster, so he goes to Dino World in an attempt to hide from it. But because the monster is created by Harry's imagination it materialises in Dino-world and terrorises Harry and the dinos until Harry imagines the monster as harmless and friendly./ Harry is upset to learn that he must return his library book so decides to hide the book in Dino-World. Although Harry and the dinos try to entertain the book, it is unhappy in Dino-World and tries to escape. Eventually the book persuades Harry to return it to the library where there are lots more books waiting to be read.