K is for Kill: Tiger by the Tail

It appears that the Russian soldiers active in France were just the first wave of something bigger, which intelligence suggests is aimed at setting off a third world war, and that two active K-agents are the key to the plan. One K-assassin is killed while attacking a retired general. But who is the target for the second K-agent, and how might this start a major war? Steed, Gambit and Purdey need to save the world.