In 1944 Hobie Hanson's father is flying B-24s in Europe, so Hobie decides to donate his beloved German shepherd, Duke, to Dogs for Defense in the hope that it will help end the war sooner--but when he learns that Duke is being trained for combat he is shocked, frightened and determined to get his dog back.

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.