Late one Friday the 13th in November, Miss Nelson gets an alarming anonymous telephone call. She then takes an ill-starred short cut through the dilapidated and soon-to-be-razed Old East Wing. There she stumbles upon something that almost unhinges her mind and that causes her to swoon. But luckily for her, exactly one week later, and at the very same hour and in the very same spot, an old friend of hers surfaces who, putting her shoulder to the wheel, quickly unmasks the malevolent telephone caller who is bound and determined to oust Miss Nelson from Room 207, nudging her into early retirement, and -with luck- sending her packing to a hospital, clinic, or cozy nursing home specializing in nerve cases. The plot foiled, both Miss Nelson and her tenebrous alter ego, Miss Swamp, turn up trumps again and carry the day.