Everyone has quirks, the wealthy no less than mere men-in-the-street. One quirk of wealthy landowners over the last several hundred years--the building of ornate towers aptly called Follies. No purpose, except to show off what their money can do.
Ravenwood Hall has such a Folly--or did have. Sarah notices the tower when she first arrives at the Hall, late in the day . She glimpses the top of it along with the mellow roofs of Ravenwood. The setting sun lights up the lichen-covered slates with a rosy glow, and a haze softens the silhouetted chimneys and surrounding woods.
By the time the car stops outside the front door, the haze has thickened into a mist, Aunt Emma is there to greet Sarah, and the vision of the tower is forgotten.
The next day, when Sarah explores, she remembers the tower--but where is it? Aunt Emma doesn't know of any tower; did a tower ever exist? If it did, when? Evidently, if it did exist at one time, it must have fallen into ruins. But why did Sarah notice it last night? Imagination, brought on by jet-lag? Maybe her witch-ancestors are trying to tell her something?
Sarah's curiosity is seeded; she is determined to find out more about the mysterious monument. What does she discover? And what happens when the mist that greeted her on that day of arrival turns blue?