Paris is burning. In the midst of the turmoil and degradation, Donald Maclean finds love. Melinda is passionate, strongminded, independent, and American. As the Nazis enter the city, Maclean gallantly proposing to Melinda so that she is allowed to flee with the rest of the Embassy, to England. It's a match made in chaos. Back in London, Blunt is being asked uncomfortable questions at MI5 about his Communist past. He is becoming increasingly ill-at-ease with the business of spying, and quietly begins to doubt his commitment. None of the others knows, though Philby is aware that all does not seem well with the man who first inspired him to join the Party. It becomes clear that Blunt is being vetted because the Royal Family want him to work for them: he will be the next Surveyor of the King's Pictures. Maclean is also doubting: he begins to see Melinda as his light-in-the-tunnel, maybe even a way out of the secret life which he is starting to resent, and to fear. As the bombs of the Blitz rain down on London one night, he 'confesses' to his wife: he's a spy, for Moscow. She leaves him, on the pretence of returning to her family in the United States. Maclean tells no-one what he has done. He is living on borrowed time. Celebrations as Germany invades the Soviet Union: at last they are free of the massive guilt and moral ambivalence of working for a regime seemingly in league with Hitler. The four once more 'on the side of the angels', but their sense of relief doesn't last long. Philby is under pressure at work: an American intelligence officer - James Jesus Angleton - seems to be watching over his shoulder at every move. Philby finds it hard to shake him. Maclean - alone and tortured by Melinda's absence - finally confesses to Blunt: Melinda knows their dark secret. Blunt deeply disturbed, rattled. He notifies their new Soviet contact: he wants out of the game. But it's not as simple as that: this is not a gentlemen's club. Blunt promises to reveal the intimate secrets of the Royal Family - the Soviets are seduced: they think the Windsors matter in politics, and besides, Stalin likes the gossip. Blunt is off-the-hook, for now. But how will he tell the others? Disaster. A former Soviet agent, Walter Krivitsky, wants to defect: if the West takes him in, he will give them information about a mole inside British intelligence. He drops a juicy clue: the mole is 'a tall, fair, Scot with Bohemian tastes'. Maclean. Krivitsky must be 'taken care of '. Philby and Blunt arrange Krivitsky's murder in Washington. Blood on their hands. Blunt, now more intent than ever to get out of spying, needs security. The King - George VI - sends him on a mission to newly liberated Germany: there are certain embarrassing, compromising letters which belong to his brother, the former king. It would not be wise for these letters to get out, become public knowledge. The King depends on Blunt to retrieve the letters from the hands of the Americans, and keep the material and its content discrete. Blunt assures the King: he can count on him. He tells Philby he's assured the safety of the four, but Philby sees through him: Blunt hasn't done it for them; he's done it for himself. And the rest? Paranoid, lost Maclean.