CITADEL OF HOPE: Heart of Darkness

Life is not going to be the same again. Sunday arrives at a boarding school for the first time.
Everything appears normal but the school is built on the dark places of the earth-- a graveyard harboring the most nefarious ghosts and vilest demons. Encounters with angels and demons are very common here.
The principal and senior staffs are deep into occultism. They are known to have heart of darkness. They conspire to cover up evil activities and evil deny the existence of angels and demons. When some students begin practicing exorcism, they are punished and turned into zombies temporally. More students become zombies for one offense or the other.
When 3 students die under mysterious circumstances, the school authority claim they committed suicide. As Sunday forms alliance with his friends to battle these occultists he discovers graveyards have already been dug with their names inscribed on it.
They have few hours to destroy the men with heart of darkness and reverse the impending zombie apocalypse.