The Corners of the Globe. (The Wide World - James Maxted 2)

Spring, 1919. James 'Max' Maxted, former Great War flying ace, returns to the trail of murder, treachery and half-buried secrets he set out on in The Ways of the World. He left Paris after avenging the murder of his father, Sir Henry Maxted, a senior member of the British delegation to the post-war peace conference. But he was convinced there was more - much more - to be discovered about what Sir Henry had been trying to accomplish.
And he suspected elusive German spymaster Fritz Lemmer knew the truth of it. Now, enlisted under false colours in Lemmer's service but with his loyalty pledged to the British Secret Service, Max sets out on his first - and possibly last - mission for Lemmer. It takes him to the far north of Scotland - to the Orkney Isles, where the German High Seas Fleet has been impounded in Scapa Flow, its fate to be decided at the conference-table in Paris.
Max has been sent to recover a document held aboard one of the German ships. What that document contains forces him to break cover sooner than he would have wished and to embark on a desperate race south, towards London, with information that could destroy Lemmer - if Max, as seems unlikely, lives to deliver it...