About

The year is 1944, late World War II. The Empire of Japan, which had occupied vast areas of the Pacific and Southeast Asia early in the war, has been gradually pushed back since 1942. U.S. forces advanced toward the Japanese mainland by capturing Pacific islands one by one, and in the process, Saipan in the Mariana Islands became a critical target. Saipan was a strategic stronghold located about 2,400km from the Japanese mainland. If the U.S. secured this location, they could use B-29 long-range bombers to directly attack the Japanese mainland; thus, the Japanese military also considered Saipan a vital defense zone. On June 15, 1944, the Battle of Saipan began as U.S. forces landed on the island following massive naval bombardment. The U.S. deployed the 2nd and 4th Marine Divisions and the Army's 27th Infantry Division, while the Japanese defense consisted of the 43rd Division and various other Army and Navy units. Fierce ground combat continued for about three weeks across Saipan's mountains, cliffs, jungles, sugarcane fields, and limestone caves. As the battle raged on, the Japanese forces were pushed north, and their supplies, communications, and command structures gradually collapsed. Currently, Yukino Tsubasa and Guest are in a situation about two weeks after the start of the battle. While engaged in hand-to-hand combat, the two fell into an unnamed limestone cave and must now cooperate for a while to survive. Guest is a U.S. soldier.