The Hood sabotages the Red Arrow aircraft programme. One of the planes crashes into the TV Tower in England during a brutal rain storm, and International Rescue is summoned to save the engineers inside the tower before it collapses; making their job trickier apart from the driving rain and winds at the site is that the Red Arrow's director, a long time friend of Jeff, is fired from the project and stays at Tracy Island, forcing the Tracys to draw him away and thus remain oblivious to International Rescue's existence.

Brains and Tin-Tin set off on an expedition to retrieve sunken treasure from Lake Anasta. The Hood has also set his sights on the riches and plans to put both Brains and Tin-Tin in grave peril.

When the Ocean Pioneer tanker inexplicably explodes, Brains investigates the cause. With some help from Lady Penelope, he discovers it to be a chemical reaction between the cargo of liquid Alsterene and OD60, which is found in the sea. International Rescue set out to save the crew of the ill-fated Ocean Pioneer II.

A new invention – the Crablogger (a nearly fully automated logging machine that converts wood into fuel) — threatens widespread devastation if it collides with an unfinished dam, after its drivers collapse due to food poisoning.