This book is quite enjoyable. The title character is Feliks Kschessinsky, a Russian anarchist who is trying to assassinate Prince Orlov, a Russian prince who is making a deal with the English government. Set in 1914: Germany is about to start a war, and England wants Russia to be their ally. Orlov is sent to negotiate with Walden, a House of Lords member and ex-British ambassador for Russia. Feliks wants to assassinate Orlov while he is in England so that the Czar is angry, that the alliance will never happen, so many young Russian people will not go to war.
The plot is tangled with the fact that Lady Walden was once Feliks's lover.