Powerscourt, coaxed out of retirement one last time, heads for St. Petersburg, where a British diplomat has been discovered, his throat cut, on a bridge spanning Nevsky Prospekt. It would seem the man knew a secret — and it proved fatal. As Powerscourt paces the Winter Palace and ponders the mystery, other matters press in on him. With Russia edging towards revolution, he must make his escape, before time runs out on him too.