Richard Hammond sets out to explain what lies beneath the ground we stand on, using 3D graphics and satellite imagery to strip away the crust and show the machinery underneath. He traces the forces that build volcanoes and trigger earthquakes back to the movement of molten rock and shifting plates far below the surface, and follows the geological processes that compress carbon into diamonds and concentrate other minerals into the deposits companies now mine for. The presenter travels from the ice sheets at the poles to the heat of the equator, using each location to illustrate a different part of the planet's internal structure, from crust to mantle to core. Hammond's approach favors visual demonstration over dense narration, leaning on graphics to make invisible processes, like convection currents or tectonic pressure, visible and explaining why certain regions of the world are so much more volcanically or seismically active than others.