Teenagers from Dimension X (S02E11)

The Neutrinos return to Earth after hearing in on the plan of Krang and Shredder to get rid of the turtles via brain-drain. Shredder finds interest in their Starmobile's ability to open dimension portals and tries to get his hands on it, and meanwhile the turtles try to get the Starmobile's main energy source running again. (iTunes)