Atlas perdu, L’

This is the second instalment in a 3-part series. In this book Jean travels to Rome to find a missing atlas which will help his mother return to her own body. He soon discovers that he is invisible and that the missing atlas has been stolen by his neighbour and friend, Alex. After escaping from an ancient pyramid, the two boys find themselves reunited once again in an alternate world where they meet themselves as adults. At the end young Alex has learned not to take things without asking.