Carrie's best friend has an accident and can no longer make the round-the-world trip they'd planned together, so Carrie decides to go it alone. Violet is also travelling alone, after splitting up with her boyfriend in Thailand. She is desperate for a ticket on the Trans-Siberian Express, but there is nothing available. When the two women meet in a Beijing Hotel, Carrie makes the impulsive decision to invite Violet to take her best friend's place. Thrown together in a strange country, and the cramped cabin of the train, the women soon form a bond. But as the journey continues, through Mongolia and into Russia, things start to unravel – because one of these women is not who she claims to be…