The Last House on the Cliff by Anne Wyn Clark

On the death of her aunt Gwyn, Lowri returns once more to Gwyn’s home on the remote island of Anglesey, Wales, with young daughter Ruby in tow. Lowri hadn’t seen her aunt in years, but this beautiful island offers a fresh start.

Yet right away, strange things begin to happen. Ruby insists an old woman is visiting her when no one else is watching, and a tattered old doll keeps being left for Ruby to find.
Then Ruby goes missing. Desperately seeking answers no one seems to have, Lowri looks to her dark family past for clues. But the secrets she uncovers suggest that Ruby is not the only one in danger, and time is running out – for both of them…