The
Crablogger, a huge
logging vehicle powered by liquid fuel and an
atomic reactor, has been built for use in the forests of South America. The night before the Crablogger leaves its base camp on its first expedition, project leader Jansen takes the crew out to dinner at Sanchos, a restaurant with extremely poor hygiene. They order a "special", which turns out to be a disgusting stew. The next morning, shortly after the Crablogger begins operations, the crew pass out from
food poisoning. With no one at the controls, the machine veers off course towards the village of San Martino and the nearby San Martino Dam. Although the village is safely evacuated, a collision with the dam will cause a nuclear explosion and widespread flooding. Jansen radios International Rescue for help in stopping the Crablogger.
Jeff dispatches
Scott,
Virgil and
Brains in
Thunderbirds 1 and
2, then contacts
Lady Penelope in England and tasks her with obtaining the Crablogger's emergency shutdown sequence from Jim Lucas, the vehicle's designer at Robotics International. As the Crablogger tears through San Martino and moves on to the dam, Penelope and
Parker proceed to Robotics International's headquarters in
FAB 1 only to find that Lucas has gone home for the night. Using a hypnotic ray on a security guard, they find a personnel file with Lucas' address and drive to his home, but are delayed en route by coming across a road accident victim. Reaching the danger zone, Brains and Virgil transfer to
Thunderbird 2s
Mobile Crane and intercept the Crablogger. Donning jetpacks and boarding the vehicle, they cut into the cockpit with lasers and have the crew airlifted to hospital. Breaking into the sleeping Lucas' house, Penelope wakes him at gunpoint and orders him to recite the shutdown sequence into a tape recorder. She then shoots him with a tranquilliser to send him back to sleep and relays the information to Brains and Virgil. Brains inputs the sequence, but it will take three minutes for the Crablogger's reactor to power down and the dam is straight ahead. Eventually the vehicle comes to a halt on a crumbling ridge. Scott arrives in a tanker and passes its lines over to Virgil and Brains, who pump out the Crablogger's remaining fuel to avert a large explosion that could threaten the dam. Their job complete, they fly to safety in their jetpacks moments before the ridge collapses and the Crablogger falls to the ground. The vehicle is destroyed but the dam is untouched. Lucas, who thought that his encounter with Penelope was just a dream, is stunned to learn of the events and accidentally lets slip the encounter with Penelope much to the irate suspicion of his wife. ==Regular voice cast==