A powerful underwater seaquake turns a busy day for International Rescue into a perilous one. Gordon's mission is to rescue a research team trapped in an undersea lab, but in doing so he discovers a chain of seismic destabilisers positioned along the bottom of the ocean floor. Lady Penelope is contacted to help the Thunderbirds find the person responsible.

John and Brains must track down the source of the seismic destabilisers. Meanwhile Scott and Virgil race to Taiwan when one of the undersea quakes destabilizes a solar collector dish in Taipe. When the sun rises on the dish it will reflect on the city burning it to the ground. All the while Lady Penelope tracks down a fearsome new adversary...

Alan is on space junk duty. Things take a turn when one of the pieces of debris turns out to be a heat-seeking SAT-MINE that activates and locks onto TB3's heat signature. Alan pulls some incredible moves in order to dodge the mine, but he can only outfly it for so long before exhaustion kicks in.

Scott rushes in with Thunderbird 1 to check out an unusual radiation spike from a remote corner of Africa - and discovers the source to be a leak of unstable uranium.

Kayo departs on the newly upgraded Fireflash plane, but soon discovers that there is a saboteur on board. Meanwhile Virgil, Allan and Gordon must help save the passengers from harm.

An anti-technology group called The Luddites power up an electromagnetic pulse device underneath London, crippling everything that uses electricity.