Hiroshi "Hiro" Tanaka, a 25-year-old office worker, meets an unexpected and tragic end when a sudden accident claims his life. But instead of fading into nothingness, he wakes up in a strange world governed by RPG-like rules. The landscape is unfamiliar—rolling fields, towering castles, and dark dungeons teem with monsters and dangers. Hiro quickly learns that he's not alone; people from different dimensions, each with their own life and story, have been summoned by a mysterious force known only as The Entity.