By summer of 1944, America is gaining the upper hand in the Pacific War with better training, troop numbers and supply lines, but the Japanese dig in and exact brutal tolls with each foothold. The U.S. aims for the heart of Japan's inner defense ring, engaging in a historic naval battle for Saipan in the Marianas. The nearly month-long battle on this island featured mountain sieges, Banzai attacks, white-knuckled dogfights, and escalating tensions between the U.S. Army and Marines. Color combat footage and testimony from the soldiers who were there bring this seminal moment of the Pacific War to life. America plans to rush into service the new top-secret, long-range Boeing B-29 bomber to strike directly at the mainland.