The spirit of the Earth, Gaia, gathers five youngsters from around the world and gives them rings that can summon Captain Planet, an environmental superhero; the newly formed Planeteers must stop Hoggish Greedly before his oil rig pollutes the coast.

Verminous Skumm revives a factory and creates an enormous acid rain cloud that endangers a city.

The Planeteers travel to Thailand to stop Greedly and Rigger's mining activity.

Verminous Skumm poisons the water supplies in South America; the Planeteers become infected by Skumm's disease and turn into rat hybrids.

The eco-villains capture Captain Planet and demand a ransom payment in the form of nuclear waste; the Planeteers plot a daring rescue mission.

The Planeteers fall under the sway of the charismatic Zarm; Ma-ti stays with Gaia and needs to convince the others to come back.