It is just before the outbreak of World War I and Britain must enlist the aide of Russia.
Czar Nicholas's nephew is to visit London for secret naval talks with Lord Walden, who has lived in Russia and has a Russian wife, Lydia. But there are other people who are interested in the arrival of Prince Alexei: the Waldens' only daughter, Charlotte - willful, idealistic, and with an awakening social conscience; Basil Thompson, head of the Special Branch; and, above all, Feliks Kschessinky, the ruthless Russian anarchist.