In London, Burke investigates two murders. The victims, a German electronics expert and a Yugoslavian engineer, had one thing in common: they both died after telephoning a certain number. Burke uncovers an intricate plot involving a password that means instant death, tin mines that have poison gas in the ventilating system, and a new, deadly Soviet satellite. Behind it all is megalomaniac who plans to destroy all the top people in England and take over the nation. Burke saves the day, but not before the Russians conspire to lead him to the brink of disaster.