Who was Mr. Asmodeus? He came into Marie's life when least expected...and left without being seen by others. What stranger powers did he control? Marie Holt's fiance Hugh hinted darkly at the old man's "illegal" past, but Marie knew him only as a kindly white-haired stranger - a patron of the arts who had offered to recoup the losses of her failing art gallery. She could not refuse his generosity, and when he had proven his honorable intentions, she could not refuse the hospitality of his Long Island mansion.

But what did Mr. Asmodeus want in return? And more important - why couldn't Marie ask him this question? The mansion was a house of many mysteries - though soon it was to provide her with horrifying answers! There was a motive for the old man's kindness - and Marie knew that she had to escape! Not from the house, but from terror beyond: a nightmare that threatened her soul!

from Goodreads