In a remote diner in Phoenix, Arizona, Spectrum flight engineer Xander Story makes contact with two Mysteron agents. Story agrees to destroy Spectrum's Skybase in return for the aliens' promise that they will halt their war on mankind – he accepts a fusion bomb in a briefcase and also a large payment. Captain Scarlet gatecrashes the meeting but is shot and killed. Knowing that his body will regenerate, the Mysterons try to engineer Scarlet's total destruction in a massive explosion. Captain Blue finds his devastated corpse and takes it to Skybase. Doctor Gold finds that Scarlet's injuries are too severe, and with no sign of the retrometabolisation process taking place, he pronounces the agent dead. While Destiny and Blue grieve for their lost friend, Story plants the bomb on Skybase, set to an hour's delay. In sickbay, Scarlet regains consciousness, only to find that no one can see or hear him, and that he has somehow become intangible, yet somehow he must warn Destiny and Blue about the bomb.