The Scent of Lilacs — Barbara Hazard

Apparitions

Siblings Katharine and Edwin Whittingham have just inherited a mansion from a great-uncle they never met. But before Edwin can sign the deed to Bryce House, his uncle's will requires him to spend one full month there, nights included. Bemused by this caveat, the pair decides it must be just an aged man's whim, and they pack up their few things for the coastal town of Lechton, where Bryce House awaits them.

But the will failed to mention one thing. Bryce House is already inhabited--by a family of ghosts. Now practical Katharine must convince herself that the phantoms she sees are mere tricks of the light. But every now and again, a dashing, dark stranger appears in the garden, out of nowhere, and Katharine wishes with all her soul that he might be real, and the answer to her prayers...