1999. As London prepares for the Millennium, a serial rapist is stalking the River Thames. A junior female police officer in a world dominated by men, Detective Constable Louise Mangan is desperate for the chance to prove herself, and when she brings in the culprit almost single-handedly, she believes the people of Hampton Court can rest easy at last. But the worst is yet to come. Soon word reaches the police of a deadly criminal operation at the heart of this leafy suburb. Now Mangan finds herself undercover, getting closer to answers each day. The truth is right there, hiding in plain sight on the water for all the world to see. But she needs to watch her step - the river runs deep, and no one will be there to catch her should she fall.