Under the direction of Joseph Goebbels, Hitler's propaganda minister, the Nazis looted many hundreds of paintings during World War II, most of which have never been recovered. One of the G.I.s charged with finding them, members of the famous Monuments Men division, was the grandfather of Michael Angelo Lombroso, an amateur painter who is looking to get rich quick. Inspired by his grandfather's stories, Michael hits upon the scheme of a lifetime. One of the lost masterpieces is "The Tower of Blue Horses" by Franz Marc, a brilliant example of German Expressionism -- a genre that Michael has...