After Captain Black steals a quantity of nuclear fuel rods from a military research centre, Colonel White sends Captain Scarlet and Captain Blue to New York to work with the FBI in tracking down the Mysteron agent, now branded as an international terrorist. White addresses the delegates at a UN conference on the Mysteron threat, unaware that Black has infiltrated the UN Tower and taken over the Russian representative, Colonel Zamatev. Under Mysteron control, Zamatev questions Skybases defences, and promises to supply his own Vampire jets to guard the Spectrum base. Believing that Whites life is under threat from Captain Black, Scarlet and Blue race to the UN Tower, and as Black takes aim Scarlet bursts through a window and takes the shot meant for his commanding officer. Destiny confronts Black at gunpoint, but her feelings for her dead lover enable him to overpower her and escape. While Destiny struggles to decide whether she should remain in Spectrum, Black destroys the vehicle transporting the Russian jet pilots, who are then recreated as Mysteron agents. Learning that Trans Global trucks are transporting the missing fuel rods, Scarlet and Blue are sent to stop them. The Vampire jets attack Skybase, but are swiftly dealt with by the Angels; however, the Mysterons manage to tamper with Destinys plane, locking the controls and sending it on a collision course towards Skybase. Meanwhile, Scarlet is captured by Black, and learns that the Mysteron agent has amassed enough fuel rods to create a bomb that will blow the Earth in half…