In 1940s New Orleans, Fish Elliot is a polio-survivor with a knack for inventing and building things, and his African American neighbor Olympia is a girl with a talent for messing things up, but they are united in an effort to save a starving stray dog they call Liberty--and when Liberty is caged by a nasty farmer, they find an unlikely ally in a German prisoner of war, Erich, who is not much older than the two children.