This is one of the very early Elizabeth Peters books, when Barbara Michaels was still finding her way with this new voice. It's not as polished as the later Peters books, or the Michaels books, but it's very enjoyable.
Laurie Carlson is in Chicago, laboring on her dissertation in mediaeval history, when a very alarming letter arrives from her great-aunt, Ida Morton. Great-aunt Lizzy, Ida's younger sister, has a new enthusiasm, fairies, and is acting even odder than usual. Can Laurie please come home? Ida, Lizzy, and their brother, Ned, effectively raised Laurie after her unreliable mother, Anna, lost interest in being a parent, and she can hardly say no.
But if she had any inclination to do so, moments later the phone rings, and it's her half-brother, Doug Wright. He's gotten a very similar alarming letter. Within twenty-four hours, they are arriving at the Morton estate in the Maryland countryside. And while something is definitely odd, no one wants to talk about it. Among the changes that have happened over the last two years is that the Mortons now have household help, a man who lives in a cottage on the estate and does basic chores, maintenance tasks Ned is no longer up to, as well as the driving now that all the Mortons are elderly enough to make it wiser to leave the driving to others. Jeff seems like a nice guy, and he certainly seems devoted to the Mortons.
But weird stuff really is happening. Laurie hears flute music at night, and sees strange lights floating through the garden. She and Doug catch Lizzy sleep-walking, trying to leave the house, on one of the nights Laurie hears the music.
When Laurie discovers Lizzy has disturbingly convincing pictures of the fairies, pictures she says were taken by "one of the Wilson girls," a family that rents land from the Mortons, and shortly thereafter Laurie is nearly run down by the Morton car seemingly driving itself, she and Doug become more and more alarmed.
The story gets further complicated by the fact that Doug and Laurie don't really know each other all that well, everything seems to be directed at Lizzy and there's no apparent motive for anyone to hurt a somewhat odd but sweet and harmless old lady, and some buried family secrets that no one wants to talk about.
Not quite up to her usual standard, but an enjoyable light read, or listen.
I borrowed this book from the library.