The year is 4461. In 2312, a nuclear war occurred, which had a catastrophic effect on the appearance of the planet and the people who inhabited it. The action takes place in the giant multi-level complex Floors. The complex consists of Sections, which contain everything its inhabitants need: home, study, work, food, leisure. Everything is connected to each other by Doors, the creation and maintenance of which is the main task of the inhabitants of the Floors. The main character, Jace, will have to open them all to get answers to the most important questions: what are Floors? Who is the Emperor? Who inhabits the complex? And why can’t everyone open that very last Door?