World Navy tests of a nuclear torpedo inadvertently threaten the offshore rig Seascape. Jeff, having been invited by Lady Penelope to join her on holiday in Australia, places Scott in charge of International Rescue, with Alan substituting for Scott at the helm of Thunderbird 1. Jeff though is angered when Scott launches a rescue effort to the mid-ocean rig.

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.

The passenger aircraft Skythrust, conceived by Brains using his real name (Hiram Hackenbacker) as an alias, falls into the hands of fashion criminals who hi-jack the plane to steal a new French design from the renowned François Lemaire.

A malfunctioning solar reflector menaces the Italian coastal village of Monte Bianco, where Lady Penelope and Parker happen to be visiting while on holiday.

While Christmas preparations are underway at both Tracy Island and a local children's hospital, which is expanding to incorporate a new radiotherapy wing, a pair of criminals attempt to burgle a high-tech vault storing gold bullion.