When high-schooler Ageha Yoshina pockets a mysterious red phone card left behind in a public booth, he sets off something he cannot stop: days later his childhood friend Sakurako Amamiya, who carried the same card, vanishes without a trace. Chasing her, Ageha is pulled into Psyren, a ruined, monster-haunted world where the disappeared are forced into a lethal survival game, and his own latent psychic powers begin to wake.