As Colonel White goes missing, Spectrum suspects that his disappearance may have something to do with the Mysterons' latest threat - to use two outlawed heroes to cut down one crowned head. When the colonel is involved in the wounding of one agent and the kidnapping of another, it seems that Spectrum's worst fears have become real: their commander has been Mysteronised and is now working for their enemies! But Colonel White has not been Mysteronised. Instead, he has been abducted and brainwashed by a new, unsuspected player in the War of Nerves: the Network, a secret organisation of human collaborators working to help the Mysterons achieve their ultimate goal. With parts of his memory missing and believing he's doing the right thing, Colonel White unwittingly does the Mysterons' bidding. Captain Scarlet and the whole of Spectrum hunt him down in the hope of stopping him before the end of the threat's deadline. And this time, whether Spectrum fails or succeeds, the Mysterons' threat might mean a crippling blow to Earth's valiant defenders.