Codename Europa

Professor Gabriel Carney, an awarded scientist for designing original electronics, is assassinated at his own gadgets-fulfilled home by Captain Black, in order for the Mysterons to use his skills and knowledge of the hi-tech subject to kill the three joint presidents of the Congress of Europe, additionally recognised as The Triumvirate of Europe. The names of those three men are: Conrad Olafson, John L. Henderson and Joseph Meccini, and this specific trio of men are apparently dubbed the most powerful figures on Earth, after the World President.
The Mysterons elect Conrad Olafson as the first to be killed, whom is located in an underground suite, 40-feet underground Vandon Base, a maximum security centre where plentiful Spectrum security personnel are scattered over, and in addition, the Angels commencing repeated aerial patrols over the area and Captain Ochre acting as the officer in charge of security.
Their attention is diverted instantly by a realistically audible incoming military assault & tank formation on the far West Sector of the base, which Carney has simulated by broadcasting recorded sound effects of a real attack via expensive speakers.
While is equipment, located in the far woods 1 mile away, has the attention of all security officers of the base, Carney infiltrates the un-guarded East Sector and drops an incendiary device into an air-vent. Thinking the bomb has plunged 40-feet below to destroy Olafson's underground suite, it has in fact stopped at ground level, thanks to Spectrum's rational ingenuity by converting the air-vent into a dummy inlet and cutting of it's air-duct, but the explosive fully demolishes the main building above ground.
With Olafson safe, leading to the Mysterons into believing he is dead, Spectrum are left with no clues of which of the remaining two joint presidents is next on the assassination list: Henderson, or Meccini. Even though they are both protected at separate maximum-security locations, Spectrum realise that this mysterious Mysteron agent is one of the toughest and challenging they have ever faced, and is capable of killing both men.