Thompson assigns April to research the growing rat infestation. She is pursued by an army of rats and escapes on a passing city bus.

A robot warrior arrives from 400 years in the future in 20th-Century New York.

Krang's computers detect an alien metal on the surface of the Earth. Krang sends Shredder, along with an Alien Metal Detector, to the surface to find it.

Full of self doubt, Leonardo leaves the team. Michaelangelo, Raphael, and Donatello all take turns being leader as they try to figure out why the sun is getting smaller.

While searching for a device to transform crude oil into liquid hydrogen, Krang accidentally brings Mr. Ogg from Dimension Z to earth.

The Technodrome is up and running again, and it is up to the Turtles to hinder Shredder and Krang from getting to the surface.

With the Technodrome in serious need for new equipment, Bebop and Rocksteady are sent to Earth, disguised in human form, to capture the Channel 6 building and return it to Dimension X.