In August of 20XX, a mysterious gate suddenly appears in modern-day Tokyo’s Ginza district. Warriors who appear to be from middle-age Europe, monsters (e.g. “orcs” and dragons) and other fantasy-like beings pour out of the gate killing many Tokyo citizens in the name of conquest. The Japanese Self-Defense Force (JSDF) is quickly mobilized and defeats the invaders using superior modern weaponry and tactics, but the mysterious gate remains. The Japanese government decides to send part of the JSDF to investigate the alternate world beyond the gate. Led by otaku soldier Lt. Itami,Youji, an Intelligence and Reconnaissance platoon (Recon 3) discovers that villages in the world are being attacked by a flame dragon. An elf girl, the sole survivor of one such attack, joins the group as they travel across this dangerous new world.