On January 16, 1957, a rocket takes off from the Baikonur cosmodrome on the orders of General Oufa of the Red Army, seeking to keep its lead over the United States in the conquest of space.

Defying the orders of Ufa, Voronov forces his assistant to continue his research to understand why young rats turn out be healthy carriers.

His spy, who turns out be Nastasia Wardynska, recruited by Captain Blake ten years previously, promises to send a sample of the bacteria next month.

Voronov realizes, and after having confirmation of the betrayal of his assistant, locks her up at the headquarters of the KGB in Moscow, Lubyanka, under the custody of General Orloff and Colonel Ilkor.

To do this, he takes as a cover the identity of Mac Taser, interpreter of Professor Philip Mortimer, official guest at the International Congress in Moscow.

But while the Russian talks of young rats, Voronov surprises the two men behind the scenes and stops Ilioutchine while Mortimer narrowly escapes death.

The next day, Blake infiltrates the Lubyanka disguised as a KGB officer with a fake transfer order regarding Nastasia, but Olrik awaits him and unmasks him.

While that the death of personalities around the world keep coming, Mortimer travels to Liverpool, where one of his colleagues has discovered that it is the thymus of the young rats that allows them to resist the bacteria.

Thanks to the documents exchanged between the two tentatively Allied blocs, Mortimer finds out how the bacteria comes into contact with the targets of the doctor: children who offer them flowers and a kiss.

At the same time, the Soviets arrest General Orloff and the other coup leaders and work with police from around the world to dismantle the network of sleeper agents.