We have frightening enemies living among us, known by their strange dress. These so-called Shakers are shrewd and canny. . .a scourge; a tumor that must be sliced from our side . . Sister Rose Callahan read the printed flyer and shivered. Its message terrified her. She was aware that Believers had sometimes been objects of resentment from the outside world, but nothing like this. Who could write such things? And who could be responsible for recent acts of violence directed against the peaceful Shaker community? A sister had suffered a mysterious wound to the head; a sackful of rats were set loose in the schoolroom, food had been stolen -- and now a hate-filled message points to continued mischief. Sister Rose, recently honored with the position of Eldress despite her youth, seeks clues in the journals of her aged predecessor. She discovers a shocking similarity to outrages perpetrated years before, as well as a scandalous secret about a present-day sister. Now Rose must look both outside and within the cloistered religious community to find clues that link an old murder, a recent death, and an unknown enemy whose thirst for revenge overrides the ultimate sin...of murder.