Winter, 1917: In St. Petersburg snow is falling, and Russia is on the brink of revolution. Outside the Smolny Institute for Noble Young Ladies, an English governess is waiting for her young charge to be released from school. But so are the Tsar's secret police. Beautiful and headstrong, Sashenka Zeitlin is just eighteen years old. In the evenings, when her banker father is doing deals and her mother is partying with Rasputin and her dissolute friends, Sashenka becomes Comrade Snowfox and slips into the frozen night to play her part in a game of conspiracy and seduction that will usher in a brave new Communist world. Twenty years on, and Sashenka is married to a high-up apparatchik in Stalin's government. She seems to have everything—yet all around her, her friends are being arrested and people are disappearing. Then Stalin himself comes for dinner, and Sashenka falls passionately in love, thereby setting in motion a terrifying sequence of events that will result in her having to make the most agonizing choice of all: whether to sacrifice her own life or that of those she loves most dearly.