Having avenged the killing of her cop-husband Joe in Cop Without a Shield (1983), N.Y.P.D.'s Sergeant Norah Mulcahaney is back on the force--now assigned to the Central Park stabbing death of naive young Nancy Hurlock, a bank teller whose over-protective father is head of Mercury Courier Service. Then two more women are killed with the same M.O.: May Guttman, promiscuous waitress at a Far Rockaway truck-stop diner; and retail executive Lila Cestone. What's the connection among these crimes? And do they also link up with the killing of a nun at the impoverished Church of Our Lady of Perpetual Help? Those are the questions for both Norah and Far Rockaway police detective Gary Reissig. And a motive does at last begin to surface--when Mercury Courier Service is hit with an $8 million robbery . . . and when a gold chalice (stolen from Our Lady of Perpetual Help) turns up in Lila Cestone's apartment, leading Norah to small-time hood Frank Salga & Family. Fast-paced, densely plotted: one of O'Donnell's most satisfying outings, with the gritty police-procedure lightened by Norah's efforts to cope with widowhood.