Nightland

The sun has gone out. Humanity survives inside a colossal pyramid, the Great Redoubt, while monsters hunt through the darkness of the Night Land outside its walls. Warden Cave begins having strange, recurring dreams of a garden and a woman whose face he never sees — until he recognizes her voice in a distress signal from the long-lost Lesser Redoubt. To save strangers he's never met, he'll lead a team into a wasteland no one returns from. 

Based on William Hope Hodgson's novel The Night Land.