Maggie O'Shaughnessey is terrified. Something evil is loose on Cape Cod. A young girl's body has just been discovered and soon Elizabeth, one of Maggie's closest friends, is savagely murdered. Now Maggie learns she has been marked as the next victim. Her stalker is clever and an excellent actor, a respected businessman and the last person anyone would suspect. Maggie accidentally discovers his identity but her hysterical accusations following Elizabeth's murder make it difficult to believe her now. Alison and Dorinda safeguard her by assuring she is never alone, and for a time this works. One day the killer's tentative hold on sanity slips, stalking her, tormenting her, is no longer enough. He must now possess her totally and make her pay for his patient endurance.