During the height of World War II, a group of Nazi soldiers encounters a terrifying mystery upon taking over an ancient fortress in Romania. From the very beginning, the atmosphere is oppressive and strange; the building, made of dark stone, has an unsettling aura, as if its walls hold dark secrets. When strange occurrences begin to unfold, the soldiers, in their arrogance, unleash a demonic creature trapped within the fortress—an entity that feeds on fear and despair.
As the Nazis confront their own creation, an enigmatic Jewish prisoner manages to escape and becomes the only one who can help unravel the mystery of the creature. With the assistance of a scientist seeking to understand the nature of evil and a captive woman who shares a special bond with the fortress, the protagonists fight for survival and seek to uncover the truth behind the entity that terrifies the occupants.
As the situation becomes more desperate, the boundaries between good and evil blur, and the characters must confront their own personal demons. With a blend of psychological horror and supernatural elements, the fortress serves as a reflection of the inherent evil in humanity, while the protagonists struggle to escape their tragic fate and unveil the secrets that lie in the darkness.