Illuminati

Read The Man from St. Petersburg by Ken Follett.

The backdrop is the pre-world war time of 1914.Britain is frantically in need of help from Russia to fight Germany.
An assassin from Russia is hard bent on sabotaging the treaty talks by killing the prince, who is indulged in leading the innocent Russian peasants to the bloody war.
A hard and cold man, Feliks can handle many weapons and he has to face various hurdles. The Scotland yard, British police, a courageous British lord...
But that is not the worst. He also has to face the woman he once loved, when he was a merry student having no ideas of what oppression is.
Now, he has to fight for what he believes for, but to do that, he has to guard himself against his long last love and it's fruit. But can he do so? Can he really face the turmoil and complete his mission? He has to lose one to get another and Feliks has no idea which one he craves more for.