The Boy in the Iron Box (1970)

Sinopsis

A mercenary team’s plane goes down over a desolate, snowbound mountain. Hoping for shelter, they stumble upon a labyrinthine stone fortress that offers no escape from the bitter cold, or the nightmares inside. As the walls close in and the true nature of the structure reveals itself, a new kind of horror emerges. This isn’t survival. It’s something else entirely...