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...

Lacey Flint, Sharon Bolton's enigmatic protagonist, has been living in a houseboat on the River Thames, and she's becoming a part of London's weird and wonderful riverboat community. Against her friends' better judgment, she's taken up swimming in the Thames, and she feels closer than ever to Detective Mark Joesbury, despite his involvement in a complicated undercover case. For the first time in her life, as she recovers from the trauma of the last few months, Lacey begins to feel almost happy.

Then, at dawn one hot summer morning while swimming down the river, Lacey finds the body of a...