22-year-old Ryouta is an unemployed good-for-nothing who spends his days living at home and playing Btooom, a wildly popular online game that's sold over three million copies worldwide. Alongside other teammates, Ryouta battles it out with others using powerful bombs and sonar that can reveal hidden enemies, and his dedication has earned him the title of Japan's top player. But soon, Ryouta's pastime becomes a terrifying reality, as he and many others are dropped onto a tropical island and forced to play Btooom – but this time for real. Now, he and the rest must fight to the death by whatever means necessary, as the only way to win this deadly game is by killing seven of the other players.