Surplus by Sylvia Stevenson

Often the road to heaven on earth – which some call happiness, and some mirage – is a tangled pathway, broadening slowly as it winds along, till as last the haven is in sight. But now and again, there is no road at all. One step out of the thicket, and there are the white walls and golden turrets, so near they dazzle you.

So it was for Sally Wraith. She came out that June morning…expecting simply to give a message to a friend of Miss Landison’s. And that morning she first met Averil.