I often wondered why I was so susceptible to Dr. Darwin's strange request, for the dangers in accepting it seemed clear from the first. Perhaps it ws the certain tender look he gave me. He said he wanted me as more than just a companion to old Mrs. Twining. I was to watch the grasping relatives who stood to gain a fortune from her death--and to see if there were some unnatural cause for her suspiciously sudden decline. As my attraction to Dr. Darwin grew, the true reason I had been lured to Twining Manor began to dawn on me--a reason that marked me for murder, and an eerie visitation from another world....
Used availability for Dorothy Daniels's A Web of Peril
1970 : USA Mass Market Paperback