Seismologist and his son Robert and Aiden Williams come across a wildcat automated Hydro-methane Mining rig. They investigate and when they start to alert the authorities, an earthquake caused by the machine opens up the Earth and swallows the machine whole - with father and son inside. Gordon makes a daring underground rescue in TB4 to retrieve the boy and his injured father while Virgil must find a way to shut down the out of control rig using TB2.