In "Special Assignment," the SPV's function as an assault vehicle (based upon its origins as a modified tank) becomes the focus of the plot. The Mysterons wish to break through security at Nuclear City with an SPV, and are hiring Captain Scarlet, now stripped of his captaincy, to help. Scarlet is actually a double agent working for Spectrum and manages to fool the Mysterons by acquiring and driving the SPV for them. In order not to break his cover, when Scarlet requisitions the SPV, he cannot show his Spectrum ID card and has to knock out the attendant of the gas station where the SPV was stored. Scarlet, to warn the Angels of the status of the SPV without breaking his cover to his Mysteron passengers, causes the SPV to emit black smoke. Scarlet ejects from the SPV and the Angels destroy it before it reaches Nuclear City.