Seeking adventure during a school field trip, fifteen kids stumble upon a strange man in a cave, who invites them to play a game. But it turns out, the game is all too real.

Questions remain in the wake of Takashi's death, the most pressing of which being, how did Takashi die? Both the kids, and the police, want to know. Amidst the grief and uncertainty, the next pilot is chosen.

Masaru's family life has made him come to divide the world into two types of people: those born to die, and those born to survive. When it's his turn to fight to protect Earth, which type will he end up as?