The crew of a Crablogger, a giant tree-eating machine, stationed in South America, go out for a meal. The
programmer, Franklin, is ill afterwards, but everyone else appears to be okay.
The Crablogger sets out next morning, but the drivers, Peterson and McCall soon fall victim to food poisoning like Franklin, and
pass out, with the Crablogger headed for the village of San Martino and the nearby dam. Base control contact International Rescue.
Scott sets off immediately, but is soon informed that they will need to contact the designer of the Crablogger, Jim Lucas, as
only he knows the emergency shutdown procedure. Lady Penelope is dispatched on this errand, and Virgil and Brains set off for the
danger zone in Thunderbird 2.
San Martino is evacuated just as the Crablogger arrives. International Rescue arrives on the scene not long after this, but they
still need the shutdown procedure.
Virgil and Brains board the Crablogger and begin to evacuate the unconscious crew.
Lady Penelope breaks into Lucas' house after stealing his address and gets the shutdown sequence from him at
gunpoint. She relays
this to the boys, and they manage to execute it, but there is a three minute delay built into the system!
Scott heads out in a service tanker to drain the fuel tanks. The Crablogger stops, but the cliff ledge that it has stopped on is
unstable and crumbles beneath them.
Virgil and Brains hook up the pipes, and the fuel is drained just before the ledge gives way and the Crablogger falls down the
cliff. Virgil and Brains use their jet packs to leave the Crablogger safely.