While practicing their martial arts in Central Park the Turtles witness an alien spaceship crash into a small pond. They dive in and rescue the pilot, he warns them that they must find the 'Three Fragments of the Eye of Zarnof'. The alien tells the Turtles that when the three pieces are joined together, they will bestow power unknown to any earthling. He gives them a Crystal Converger to help them locate the Three Fragments before they fall into the wrong hands. (thetvdb.com)