The Tartarus Tower is a Jail in Hell for Demons who have committed a grave sin in Hell. The tower is so high that its peak ends in Heaven. This is the place the outcast demons want to reach. But the guards of the tower are Angels and they want to prevent the demons from reaching Heaven.
For their offense, the demons must fight for survival in the tower. The tower consists of 70 floors and each pose various dangers. For each floor of the tower, there are a number of points which the prisoners must achieve, otherwise they will not be able to advance to the next floor.