The Attic Child — Grace Corren

Marla Doren came to the isolated Adirondack summer home of Garman Gibson with a new feeling of security. As tutor to the two Gibson children, she could at last pay off the debts of her ailing father.

Beechhaven was a strange, huge old house, with rooms that seemed to appear and disappear at will; with two children whose playmate was a boy, dead many years; with a man who could apparently be in two places at once -- and a secret room that held a mind-boggling wealth of treasures...

And the Tim Layard turned up - Tim, whom Marla had once loved and lost. Tim was on oddly familiar terms with the Gibsons, although he never told Marla his reasons for being there. But her curiosity about him was wiped from her mind by fear when it became evident that someone was trying to frighten her away -- or kill her.