

Mysterious and unearthly deaths start to occur while Professor Saxton is transporting the frozen remains of a primitive humanoid creature he found in Manchuria back to Europe.
Acting
Lee and Cushing's rival chemistry elevates every scene they're in.
Practical Effects
Glorious red eyeball effects and that creature design — budget magic.
Production
Spanish studio pretending to be Siberian railway — charming fakery.

Director
Eugenio Martín
Trivia, insights & behind the scenes
The train interior sets were reused from Pancho Villa (1972), which is why everything looks vaguely Western.
Marketed as a straight Hammer-style horror in the US, but it's actually Spanish exploitation cinema cashing in on Lee and Cushing's British star power.