The circumstances that left hundreds of thousands of Allied troops surrounded by Nazi troops and trapped on the beaches of Dunkirk in May 1940 are messy, convoluted, and marred by militaristic debate. Director Christopher Nolan's treatment of "Operation Dynamo," the effort to smuggle those men out through waves of air raids and U-boat torpedo attacks, is not. Intricate yet simplistic, like the pocket watch one hears tik-toking behind every bar of Hans Zimmer's propulsive score, Dunkirk is an elemental chronicle where each path of escape -- by land, by sea, by sky -- diverts back to the Hell on earth that was World War II. There aren't so much characters as there are factions of men, soldiers and British amateurs looking to lend a hand. There's no plot beyond "get the hell out." But in Nolan's hands, and through IMAX-sized frames, it's a mesmerizing, maddening, and often isolating experience -- this was real life.