In New York, mysterious radioactive ooze has mutated four sewer turtles into talking, upright-walking, crime-fighting ninjas. The intrepid heroes -- Michelangelo (Robbie Rist), Donatello (Corey Feldman), Raphael (Josh Pais) and Leonardo (Brian Tochi) -- are trained in the Ninjutsu arts by their rat sensei, Splinter. When a villainous rogue ninja, who is a former pupil of Splinter, arrives and spreads lawlessness throughout the city, it's up to the plucky turtles to stop him.