International Rescue are dispatched to save one of their own when the Hood traps Lady Penelope and Parker inside an underwater hyper-train loop during a high-stakes robbery.

A seismologist and his son alert the authorities to the presence of a rogue wildcat mining operation, only for the machinery to trigger an earthquake that swallows the equipment - along with the father and son. Gordon must attempt a daring underground rescue of the boy and his injured father, while Virgil has to find a way to shut down the out-of-control rig.