Brains and Alan are on a visit to the Supreme Hadron Collider when a satellite begins to fall straight towards them. They are rescued in the nick of time by the arrival of Virgil in Thunderbird 2. Examining the evidence, the team decide that the malfunction was caused by a gravity well instigated by the collider itself. Things get even stickier when a commercial jet is caught in the pull of the gravity well and is in imminent danger of crashing. Can International Rescue shut down the collider in time to save the plane and its passengers?