The World Navy is testing gyropedoes close to the oil rig Seascape. Frank gets a call from the captain of the flagship W.N.S Atlantic, who warns him there will be underwater nuclear explosions but insists that this poses no danger to them.
Flames from the Seabed
A maverick gyropedo explodes on the sea bed and is capped off by Thunderbird 4, but the gas field remains ignited and eventually breaks through again. A column of flame shoots high into the air, feeling themselves in danger, Hooper and O'Shea call International Rescue again , but Scott decides not to get involved and recommends that the Navy evacuate Seascape.
The Rig is Damaged
Another jet of gas bursts through the sea bed and the resulting wave fractures one of the rigs legs. Hooper and O'Shea go down in the diving bell to check the damage, but a third column of flame then explodes, causing the rig to slip further and the diving bell crashes to the sea bed. Hooper and O'Shea are trapped!
- Hooper first appeared in The Cham-Cham, where he made a cameo appearance as an Assistant Controller. Later in the same episode, a portrait of him can be seen hanging on the wall of Maxie's office. He appears again as the first reporter in Alias Mr. Hackenbacker, as toy packer Tanner in Give or Take a Million, and as an Indian shopkeeper in Thunderbird 6.