"I like a good detective story, but they begin in the wrong place! They begin with the murder. But the murder is the end. The story begins long before that." So remarks esteemed criminologist Mr. Treves. Truer words have never been spoken, for a psychopathic killer has insinuated himself , with cunning manipulation, into a quiet village on the river Tern. But who is his intended victim? What are his unfathomable motives? And how and when will he reach the point of murder...the zero point? In the ingenious and noteworthy departure for Agatha Christie, it's the intricate workings of a pathological mind that becomes the stuff of startling mystery as group of friends at a seaside resort remain blithely unaware that their weekend will be the death of them all...