One-shot. The Tennysons on a trip to New York are captured by Bishop who seeks to use the Omnitrix for his experiments. Escaping, Ben tries to devise a plan to get his Grandpa and cousin back from him, only to run into four brothers from the sewers who are more than happy to lend a hand. Takes place in 2k3 TMNT universe. Title is inspired by the game TMNT 3 Mutant Nightmare.