In the near future, humanity teeters on the brink of extinction.

The Adhvan Resilience School was founded to take a stand against the incoming calamity,
but one day, tragedy strikes.

Monstrous creatures known as GEMs began attacking the people,
forcing the academy city to seal itself off.

In the midst of this nightmare,
those trapped inside must face the burdens of their sins.

What truth lies behind the anomaly shrouding the city...?