Ryuji (Iwasaki Taisho), Satoru (Sato Ryuga) and Atsushi (Ukisho Hidaka) are friends in high school. They are classmates in the 2nd grade class B. They appear like troubled students, but they are not. They are actually country boys. When they are at their secret place, they suddenly feel a big shake and hear the sound of thunder. The next moment, they see a man Sanpei wearing a dirty military uniform with a backpack and holding a bayonet. Sanpei came from the past, right before the end of the war in Guam. Ryuji, Satoru and Atsushi enjoy their time with Sanpei. They think that their lives might change with Sanpei and they ask him to spend summer with them. Class President Michifumi (Nasu Yuto) and twin brothers Akihiko (Fujii Naoki) and Kazuhiko (Kanasashi Issei) join the group.