Stung by loneliness after the desertion of his wife, Sandra, and by fears for his daughter Kay, Constable Toby Ash works feverishly to identify the rapist-killer of seven young girls in the English town of Molsham. His efforts pay off. An eyewitness to an out-of-place car, a telltale whiff of chloroform, and a little white dog lead him to an all too plausible suspect: butterfly collector Bernard Jessop. Meanwhile, though, maddened with grief and frustration like so many of Ashford's lawmen, Ash drifts into an affair with flirtatious family friend Janet Howard, then watches in horror as the affair threatens to wreck both his foundering marriage and the investigation. Will Janet, who spent an all-important night at Ash's place, come through with the alibi that will seal Jessop's fate by proving Ash couldn't have faked the final damning evidence against him? And if she doesn't, how will Ash be able to face letting the man go free? The plotting may be mechanical, but Ashford (An Illegal Solution, 1991, etc.) is efficient as ever in showing the raw pain of his grimly compromised coppers.