Professor Sir Alexander Saxton boards the Trans Siberian Railway with a frozen humanoid specimen recovered from Manchuria, convinced it represents a missing link in human evolution. After a series of grisly deaths marked by bleeding, white eyes, Dr. Wells joins the investigation and discovers the victims have somehow been stripped of memory and knowledge. As the creature moves through the train, new clues reveal that the body itself is not the true danger. Inspector Mirov, Father Pujardov, Natasha, and other passengers become entangled in a desperate struggle against an intelligence that grows stronger with every mind it consumes.