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 also 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 ...

A tense and twisted psychological thriller about obsession, manipulation and toxic friendships, VIOLET also reminds us that there's a reason why mother told us not to talk to strangers ...