The race is on to be the first to discover the secret of flight! Magpie is soon caught up in a world of science, spies, and unruly animals to be the first to passenger in a hot air balloon. Yesterday, Magpie was one of the best thieves in all of France. But an encounter with a boy dangling from the sky will change her life forever. And even though it ends in disaster, Magpie becomes enthralled by the idea of flying over the rooftops of Paris like the dangling boy: Pierre. His family, the Montgolfiers, are desperate to be the first to discover the secret of flight. And Magpie has ideas, but she also has secrets. Together with Pierre, she'll need to help the Montgolfiers accomplish their dream before her past gets the best of them all. In a test of bravery, imagination, science, and friendship--Magpie, Pierre, and their pet birds are in a race against time to get the Montgolfier's in the air before the King and Queen.

It'll take two children, a chicken, a duck, and a sheep to help them find the answers. But others, too, are determined to discover the Montgolfiers' invention.