Not to Disturb — Muriel Spark

Household servants and accidental guests must wait out the orders of the lords of the house: not to disturb.

A winter's night; a luxurious mansion near Geneva; a lucrative scandal. The first to arrive is the secretary dressed in furs with a bundle of cash, then the Baron, and finally the Baroness. They lock themselves in the library with specific instructions not to be disturbed for any reason. Soon, shouts and screams emerge from the library; the Baron's lunatic brother starts madly howling in the attic; two of the secretary's friends are left waiting in a car; a reverend's services are needed for an impromptu wedding -- and despite all that the servants obey their orders as they pass the time playing records, preparing dinner, and documenting false testimonies while a twisted murder plot unfolds upstairs.