After a devastating attack on a nuclear facility, leaving only the cryptic message "VON," Japan is thrown into chaos. The government is powerless, and the police are scrambling to find the culprits.
Six months later, two teenage boys calling themselves "Sphinx" emerge, taunting the police with threats of destruction. Detective Shibazaki finds himself caught in the middle of their game, desperately trying to prevent further catastrophe.
As Sphinx's plans unfold, the anime delves into the story of Nine and Twelve, the boys behind the masks. They operate in the shadows, their actions driven by a hidden, tragic past that they are determined to expose, even if it means bringing the city to its knees.