Czech soldier Filip Sedlák never wanted to fight for the Austro-Hungarian Empire. So at the first opportunity, he defected to the Russians. Now he and others like him have formed the Czechoslovak Legion. Their goal: leave the chaos of Russia, sail to France, and help the Allies defeat the Central Powers, thereby toppling a hated empire and winning an independent Czechoslovakia.

With the fall of the tsar, Nadia Linskaya's life is in ruins. Her family is dead, her lands are confiscated, and her aristocratic world is gone forever. But Nadia is determined to elude the Bolshevik agent who destroyed her family and find a way to survive in this changed world.

When Nadia takes refuge with the Czechoslovak Legion, the last thing she expects is an ally. But when Filip proposes a sham marriage to ensure her safe passage across Siberia, she takes it. Neither Filip nor Nadia expect real love, not when the legion has to take over the longest railroad in the world—and then hold it against Bolshevik counterattacks, partisan sabotage, allied intrigue, and a set of brutal Siberian winters. At risk is the future of Czechoslovakia, the fate of Russia—and their hearts.