An enemy from Master Splinter's past is back and hungry for revenge. To get it, he'll summon the most dangerous foe that the Turtles have ever encountered-the Collectors, shape-shifting demons that can pass through dimensions at will and cannot be stopped once they have been summoned to harvest a soul. To save themselves from the clutches of the Collectors, the Turtles team up with the Ghostbusters, the only people who have ever faced them and lived to tell the tale, in a battle that turns into a chase across dimensions both incredible and terrifying.