This is the sequel to 'The Hundred Decker Bus' which my son also loves. There is an amazing fold up space rocket at the end too! In this story Ivy is a rocket ship inventor who flies to another planet and helps the aliens to tidy up their messy planet by building a 100 storey rocket! Just with the previous book my son loved the large fold out page and we spent ages looking at all the intricate details in the illustrations. I love the underlying message to look after our planet and keep it clean and tidy! A great story for all the little vehicle/space loving children out there!