A man wakes up in a building, with no memory, and starts going up the stairs. The man starts remembering his name and parts of his identity, and discovers he is on a mission in the House of a Thousand Floors, an allegory of modern society. After multiple more-or-less surreal encounters, the protagonist will eventually pierce the mysteries of the building, and of its omnipresent master, Ohisver Muller.
This novel from 1929 has been quite an enjoyable read, especially for a novel that was quite precursor in its style at the time.