Three years ago the papal airliner goes down over the jungle of Brazil never to been seen again.
Three years later those considered lost on that fatal flight begin to show up at Vatican City disconnected from reality.
When the pope is gunned down in an assassination attempt, Kimball Hayden and his team of Vatican Knights follow the conspiracy's trail to a cathedral deep inside the Brazilian jungle - a place of taboo to locals who fear the Huecuvus, the Evil Spirits who protect those within the Ruins of Lost Souls.
The cathedral is a place of damnation and dark secrets - a hub of moving shadows that reach out to Pope Pius with a hand from the past, a hand that holds a dark secret: the pontiff may not be who he appears to be, but a man whose past may have been as sinful as those within the lost cathedral, a dying breed of Nazis who once called the pontiff brethren.
As Kimball Hayden and his team of Vatican Knights try to neutralize the threat against the Vatican, they find themselves fighting against overwhelming odds. Shadows and shapes converge, the weapons they yield sharp. Can the Vatican Knights defeat a sect where life has little meaning? Does the pope hold a dark secret? Was he once evil incarnate who now sits upon the papal throne? The answers lie within a temple of ancient evil called the Lost Cathedral.