Brains and Alan visit the Quantum Research Center, adjacent to New Geneva in Switzerland, to see the Supreme Hadron Collider switched on. Disaster strikes when the collider is switched on, creating a gravity well. A satellite is sucked down into downtown New Geneva, and International Rescue is mobilised when an aircraft and the World Wide Space Station are drawn into the gravity well, threatening the city. The only craft that can withstand the gravitational pressure is Thunderbird 4, used out of its normal undersea environment.