Brains and Alan visit the Quantum Research Center, adjacent to New Geneva in Switzerland, to visit Brains' old friend Professor Moffat and the Supreme Hadron Collider. Disaster soon strikes when the collider suddenly creates a gravity well of extreme power which soon pulls a satellite down towards New Geneva. International Rescue quickly mobilizes when both an aircraft and the World Wide Space Station are also drawn into the gravity well, threatening the city. The only craft that can withstand the gravitational pressure is Thunderbird 4, which Gordon must pilot out of its normal undersea environment.