Set in a dystopian America in the near future, the story tells of the experiences of five 16-year-olds who were living in orphanages who wake up to find themselves in a strange building that has no walls, no ceiling, and no floor: nothing but endless flights of stairs leading in every direction, seemingly infinite, so that it is impossible to get one's bearings or have perspective. On one landing is a basin of running water that serves as a toilet, sink and drinking fountain; on another, a machine with lights that intermittently produces food. The five, thrown together in these bizarre circumstances, must learn to deal with the others' disparate personalities, the lack of privacy and comfort, their clear helplessness, and a machine that only feeds them under gradually more exacting situations.