Winter 1917: As a generation of Europe's young men perish on the fronts, British spy Jack McColl is assigned a dangerous sabotage mission deep in Central Asia where German influence is strong. Meanwhile, the woman he loves, Caitlin, is in Bolshevik Russia, thrilled to cover the Revolution. Caitlin knows Moscow is where she is meant to be - even if she is putting her life at risk. But years of bloody war have taken their toll on all of Europe, and Jack and Caitlin's relationship may become another casualty. Can a revolutionary love a spy? And if she does, will it cost one of them their lives?