Cosmo creates real lava flow that goes spewing out towards Vicky's house. Timmy could probably stop it in time but he decides not to, hoping that if Vicky's house is destroyed she will have to move away to South Dakota.
The CyberSquad needs to get across a pool of lava. They find tiles in the shapes of triangles, pentagons, and hexagons, and tessellate the tiles in order to create a bridge that will shield them from the heat. When they run out of triangles in the middle of creating the bridge, they attempt to use pentagons, but that shape leaves gaps, so they use hexagons to complete the bridge.
The crew explores a geocode 700 miles under the surface of the Earth. As they start cutting one of the crystals, the protective shell breaks, and lava flows through, causing the crew to rush to safety.