Sludge solves the world's trash problem by dumping everything into a volcano, which then erupts.

A dumping operation threatens an underwater city.

Sludge and Blight break into government computers and transform all national parks into toxic waste dumps.

A depressed Kwame leaves the Planeteers when no one seems to care that Sludge is burying a small town in garbage.

The teens cross paths with Cold Warrior Commander Clash, but their true opponent is Captain Pollution, a creation of Blight's.

Commander Clash joins the Planeteers to stop the eco-villains and Captain Pollution.

To make a fast buck from a trash strike, Sly Sludge steals an untested microbe from Gi's scientist hero, Dr. Helix. It was supposed to be a technological fix for the problem of overflowing landfills, but it simply absorbs trash to become a city-devouring garbage blob. The blob must be stopped before it grows out of control.

Sludge and four of the Planeteers learn first hand the terrible effects of untreated sewage when MAL and Dr. Blight shrink the EcoSub (and them) to microscopic size and put them into polluted water that Kwame unwittingly drinks. The Planeteers must battle hideous water-borne parasites in Kwame's body so that he can recover, and restore them to proper size.

As key World leaders come together under one roof to discuss how to best prevent the growing spread of pollution and o-zone damage worldwide, Zarm returns to earth with a plot to snuff out the Planeteers. Calling a meeting of all the eco-warriors greatest foes, Zarm is able to tap into earth's energies and drain the earth itself of all it's resources. Only Gaia stands in his way, but Zarm has a final surprise to ensure she does not become a problem..

Zarm, having disabled Gaia and re-taken his position as spirit of the earth, begins turning the world into little more than a dead husk. With Gaia reduced to an old woman with not much longer to live, the Planeteers and Captain Planet face their greatest threat yet...

Sly Sludge and Duke Nukem dump toxic waste in the Amazon rain forest, imperiling Ma-Ti's village. Ma-Ti returns to the village with Planeteers and find it in flames. When they fail to stop the fire, Ma-Ti hunts the culprits alone.