Beakman explains how caves are formed by acid dissolving limestone and he uses a model to show how this happens. He explains there are two major sections of a cave called the twilight zone (little light reaches in) and the dark zone (no light reaches). Beakman describes the different animals that live there and their features. They also talk about stalagmites and stalagtites and then make their own.

Beakman explains how to create a bouncing egg by putting it in a jar of vinegar for a few days. He says the shell is hard because it's made of minerals and the aceitic acid in vinegar breaks down those minerals leaving behind the rubbery texture.

The Mineral Explorers travel to Najuvan, Spain, the source of pyrite. The explorers discuss one characteristic of pyrite that is hard to believe: its perfect cube form.

Lowly Worm and Huckle Cat wonder about what kinds of gems and metals could be buried under Busytown. They think about the mining process that brings us things like jewels, iron, and more!

The dwarfs dig the mines for valuable gems to make their riches. They sing a song that describes their work.