After backpacking through Asia, a group of friends climb aboard the Siberian Express to start their journey home. Little do they know, they've bought a one-way ticket to hell, as one of them has been infected with a bioweapon that will turn them into a monster who will slaughter everyone on the train. And the bioweapon will start World War Three if it reaches its destination in Europe. Now, these friends must make a difficult choice: kill someone they love to save the world or die trying.