It's been 3 years since the defeat of Kai's evil vampire spirit. Since Kai was free from his spirit trapped in its mirror the ninja lived in peace forever, well, at least they thought. When a trip in search for underwater treasure couldn't get any worse, the spirit is free possessing one of the ninja in the process. He roams Ninjago to find a way to open a mystical portal to let free his "still alive" ancestor spirits to possess the innocence of Ninjago until no human is left unturned. Will Kai and the rest of the team conquer his spirit, or get possessed trying?