From their underground home in the sewers of New York City, the Teenage Mutant Ninja Turtles fight petty criminals, evil masterminds and even aliens. Trained by their sensei, Master Splinter, in the art of Ninjutsu, these anthropomorphic heroes are skilled ninja warriors. Though their activities remain unknown to society, they defend humanity from the dangers of the underworld and often clash with the Foot, an ancient and criminal ninja clan whose leader, Shredder, is the Turtles' greatest foe.