This is a rather lovely book for young readers aged 5-7 created by the double act that is Philip Reeve and Sarah McIntyre. They've worked on books together before and though they're usually known as author and illustrator respectively, in this book they claim to have both contributed to the story and the pictures.

Pedro is a tiny mouse looking for a big adventure but ends up being rescued by the AdventureMice, a dedicated team who protect the Mouse Islands. Pedro would love to join them but he needs to prove that he is brave enough. Then it looks like he will get his chance.

An otter is a terrible beastie. As big and fierce as a cat, as clever as a dog and as hungry as a shark. Even though the otter is a terrible threat to the mice, when he gets in trouble, Pedro determines to help him: "It doesn't matter that he's bad," he says. "What matters is we're good and that means we have to try and rescue him."

This is a fun, lively story of courage and friendship with colourful, comical pictures throughout. Lovely.