Like everyone reading the newspapers these days, 10-year-old Barney Roberts knows the killer will strike again soon. The victim will be another boy, just like him. The body will be drained of blood, and left somewhere on a Thames beach. There will be no clues for London detectives Dana Tulloch and Mark Joesbury to find. There will be no warning about who will be next. There will be no real reason for Barney's friend and neighbor, Lacey Flint, on leave from her job as a London police detective, to become involved, and no chance that she can stay away. With the clock ticking, the violence escalating, and young lives at stake, Lacey and Barney both know they can't afford a single wrong step if they hope to make it through alive.