"Ten-year-old twins Mia and Maddie and their little sister Lulu head to London for the first time to watch mom, famous singer Gloria Glimmer, perform. But on a day trip to the National Gallery, Maddie witnesses what she believes to be an art theft and takes her sisters and their beloved and wacky nanny Miss Julia on a wild and crazy adventure as they follow the supposed thief to his lair"-- Provided by publisher.