Gaia, the spirit of the planet, assembles a diverse team of "planeteers," who are able to combine their powers to summon an elemental warrior that takes on the appearance of superhero Captain Planet. He works with the planeteers to defend Earth from pollution caused by criminals and villains. As the show's theme song says, Captain Planet is "gonna take pollution down to zero" by defeating the villains, who include the likes of Hoggish Greedly, Dr. Blight and Looten Plunder. The animated series was co-created by media mogul Ted Turner, a noted environmentalist.

The Planeteers must retrieve a stolen South American artifact from Verminous Skumm.

The eco-villains crash an environmental TV show to replace it with programming dedicated to pollution; the Planeteers attempt to stop their broadcast, but Duke Nukem threatens to detonate a nuclear bomb live on camera.

The Planeteers discover Hoggish Greedly plans to kill all the river dolphins in existence.

The Planeteers must save old-growth trees from being felled.