On a mysterious deserted island, Ryouta Sakamoto, who has been thrust against his will into a vicious game of survival, manages to defeat his first enemy player. While struggling with the guilt of having murdered another person, he stumbles upon Kiyoshi Taira, an older man who fills in some of the blanks about their situation. Ryouta begins to harbor the suspicious that the company behind the virtual 'BTOOOM!' world is also behind this very real bomber death-match. Intent on escape, Ryouta ventures into the heart of the island... But then, an even more formidable foe attacks.