Casey Jones steps up and takes on pure evil. Meanwhile, the Turtles learn a shocking secret about April's past, and come face-to-face with another mutant turtle called Slash, a fungus mutant spreading through the sewers, a rewired Metalhead, and the Rat King! Includes next 6 episodes of Season 2 (continuation of "Mutagen Mayhem").
6 Animatics - "Mutations of a Scene", Featurette - "Meet Casey Jones".