Burgess, Blunt, Philby and Maclean, still ardent communists and working for the KGB, must follow instructions and cover their political leanings. They now have to convince the powers that be that they have outgrown their juvenile leanings towards socialism and become members of the British establishment to become moles on the inside. Philby is sent to Spain to report on the civil war, made to deny any German involvement, and Blunt gains the confidence of the British royal family.
Maclean marries an American woman so that he can bring her into Britain with him after the outbreak of war. Philby is back in England, working high up in the British Secret Service, using his position to supply information to the Russians. Blunt gains the trust of the British royal family and wants to pull out of British intelligence and offers the KGB to be their man inside the royal palace.
Burgess and Maclean are becoming liabilities for Soviet intelligence, and Philby has his hands full protecting the two of them before they can be pulled out and relocated to Moscow, while CIA man Angleton is becoming increasingly suspicious of Philby himself.