The Prison Beneath the Cathedral

During renovations beneath an ancient cathedral, workers uncover hidden prison cells dating back hundreds of years. A historian volunteers to investigate and discovers journals describing prisoners who heard voices from beneath the earth at night. Soon, workers begin disappearing underground. Strange chanting echoes through tunnels after midnight. Ancient symbols glow on the walls whenever candles go out. The historian realizes the prison once held people possessed by an ancient entity sealed beneath the cathedral centuries ago. Include religious horror, claustrophobic underground settings, historical conspiracies, emotional conflict between faith and fear, and a desperate race to stop the entity from escaping.