Apocalypse--What Now?

S5, E1: Centuries ago, the Codex of Saint Theopolis was lost during a raid on a monastery by bandits. In modern-day New York, Peter and Ray accidentally buy the book at an auction, when Peter sneezes due to excess dust. Janine, on her lunch break, opens the book, not knowing that it contains the spirits of the legendary Four Horsemen, who wreak havoc upon the city, and ultimately the world. Unable to stop the four specters, the Ghostbusters are joined by a priest from Greece, whose ancient Order once protected the Codex of St. Theopolis, since it was St. Theopolis who imprisoned the Four Horsemen 1000 years ago. The Ghostbusters must journey to Greece to acquire a special ring/seal before the world ends.