Ethan scales a large mountain with his bare hands. After a few close calls, he reaches the top and gets a set of special glasses, which tell him his mission.

Sid tells Manny and Diego that the floor is hot. They find out that they're walking on a bed of igneous rock when the volcano erupts. They have a few close calls but all manage to escape to safety.

Trevor, Anna and Sean are stuck inside an active volcano. Their only hope to escape is to start an eruption that will propel them out of the volcano. On his last flare, Trevor finally lights a spark between two igneous rocks in the wall to begin the eruption.

The Secret Labbers learn about gemstones from Sheila. She also gives examples of the real-world applications of minerals, such as diamonds. Watch Thomas Edison's Secret Lab on Netflix, the Kid Genius channel on Xfinity, public television and DVD. Visit EDISONSECRETLAB.COM for games, videos, downloads and more!

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.