When Olive's best friend, Walter, flies outside, she doesn't know if she will ever be able to find him. Walter is small and the city is very big. But Olive knows that her special acrobat-detective-explorer-pirate skills will help her find Walter - won't they? Can Olive find her friend? Keen-eyed readers may have to help her. Joanna Boyle is a London based animator and illustrator. Her first picture book was Tip-Tap Dancing Cat (Pavilion).