The House of Doors (Unabridged‪)‬

Bent on taking over the earth, the deadly Thone have planted a monstrous device on our planet's surface. Trapped inside is a group of scientists, spies, and innocent bystanders. Part maze, part torture chamber, part laboratory, the house of doors is a test. If its captives survive, the Thone will withdraw from earth and leave us in peace. 

Survival seems impossible. At every turn of the labyrinth, the prisoners encounter alien worlds and terrifying monsters ripped from their own subconscious fears. Only by defeating the demons within can these men and women escape the house of doors and save the earth.