One family. Nine countries. And a search for a giant mouse. When the Prior family dash through Europe and Japan on the trail of a capybara, they've no idea they'll stay in a Liechtenstein brothel, flee an Edinburgh plague doctor, join a dystopian society in Tokyo and attempt to break the German land speed record. As they sleep on the pavement, live on Nutella and dress up as cartoon caterpillars, will they succeed in their capybara quest, or will the European Christmas markets, Scottish bagpipers and the impossibly complicated Japanese train system defeat their holiday goal?