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.

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.

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. Back on Earth, Lady Penelope and Parker implement a plan to sneak into a top-secret storage facility and find the mine's deactivation code. They succeed and the mine powers down before TB3 is destroyed.

Thunderbird 5 picks up an unusual radiation spike from a remote corner of Africa, and Scott rushes in with Thunderbird 1 to check it out. Using special equipment, Scott enters the mine and discovers the source to be a leak of unstable uranium. Moments later he is attacked by a mysterious woman who claims that the mine belongs to her family. During their confrontation, the mine begins to crumble - and Scott and she must find a way out.

Kayo is riding aboard Fireflash, a supersonic airliner invented by Brains, but he is unaware that its controls have been tampered with. International Rescue notices the plane has vanished from their monitors and attempt to locate it. Kayo realises that the plane is flying in the wrong direction, and manages to avoid a powerful gas attack that has knocked out both passengers and crew.

An anti-technology group calling themselves The Luddites power up an electromagnetic pulse device underneath London, crippling everything that uses electricity. The result is a near catastrophe as the entire city shuts down. Virgil and Grandma Tracy must find and disable the device - with the help of Lady Penelope and Parker.