Description: October 22, 2001. Takeshi Shirogane, who was supposed to be living in a peaceful Japan, suddenly wakes up in a strange world. There is a "parallel world'' where humanity is on the brink of extinction due to a decades-long war with the extraterrestrial species "BETA.'' Japan was a frontline nation where the military took priority over everything else. Takeshi, who continues to be at the mercy of reality without knowing the reason why he moved between worlds, eventually accepts his fate and continues to fight alongside his loved ones as a United Nations military guard involved in the Humankind Relief Plan. However, humanity, unable to overcome the conflict of interests between nations, chooses to abandon the Earth. Three years later, Takeshi wakes up from a deep sleep and finds himself in his room, which was supposed to be in his "original world". Was it all a dream...? Takeshi, who hopes to return to his "original world", is faced with a harsh reality.