In reality, Sakamoto Ryuta (voiced by Hongo Kanata) is a lonely and taciturn otaku, but in the online game "BTOOOM!", Ryuta has become a world-class player with super strength. What Ryuta didn't expect was that one day, the fight that should have belonged to the virtual world spread to the real world, and dozens of men and women including him were forcibly taken to a deserted island by a mysterious organization, where a real-life game with the same name as the online game was being played. In order to survive, Ryuta must use his abilities to fight strangers to the end. The blonde girl Himiko (voiced by Mimori Suzuko), the former friend Oda Nobutaka (voiced by Nakamura Yuichi), the cunning and brutal Imagawa Yoshina (voiced by Nara Tetsu), and the dual personality Kira Kosuke (voiced by Sawashiro Miyuki), why were they involved in this game? Who is behind the overall situation? Everything is still in the fog.