As the United States enters World War I in 1917, newly married actor Jerry Jones puts on an all-infantry musical to raise his fellow soldiers' morale. At the dawn of World War II, as his own son, Johnny, ponders whether to marry his sweetheart, Eileen, Jerry and his old Army buddies -- including Eileen's father, Eddie Dibble-- decide to put on a new show for the boys marching off to battle just as they did years ago.