For fans of The Secret Life of Pets , this second book of a hilarious chapter book duology follows the Russell Bros. on another rip-roaring, super-secret spy adventure. When Molly Miller loses her favorite hat at the Big City Museum, the Russell brothers leap into action to retrieve it and save the day! With lots of blueprints, maps, and a unique blend of photos and colorful illustrations, this story will take young readers on an unforgettable journey as they discover whether Jack Russell, Big Russell, Just Russell, and Little Russell will be able to extract that hat.