Spy Line is the sequel to Spy Hook. Bernard Samson is on the run from MI6 in East Berlin after asking unwelcome questions about a slush fund. Eventually they settle their differences and MI6 sends him on a mission to Vienna, where he learns that his wife Fiona, widely believed to be a traitor who had defected to the KGB, was in fact a double agent. Samson is world-weary but shocked to learn that the truth of his wife’s supposed defection had been hidden from him by Fiona and by the handful of superiors who knew the truth.
A satisfying middle book in this trilogy.