Shout-Out: The Guard by Peter Terrin

In the near future, Harry and Michel live in the basement of a luxury apartment block, guarding the inhabitants. No one goes outside. The world might be at war, it might even have been plunged into nuclear winter. No one knows.

But one weekend, all of the residents leave the block, one by one. All but the man on floor 29. Harry and Michel stick to their posts. All they know, all they can hope for, is that if they are vigilant, the "Organization" will reward them with a promotion to an elite cadre of security officers. But what if there were no one left to guard?