Rich American playboy Scott left his Southern small town to explore the heady world of London's social scene. Now it all feels a bit hollow after his boyfriend abandons him. He distracts himself by playing white knight for the homeless young woman he finds wailing at Finsbury Park Station. He's convinced he can help Clotilde make a life for herself in London, if she'll just try a little therapy.
Their fragile friendship is challenged when a serial killer's victims cause Clotilde to run sobbing for the river every time they pass through Finsbury Park. The killer believes that the wrath of the river spirits will cleanse London if he can offer enough blood sacrifices to draw them nearer. His cunning has kept the police from linking the murders so far. But no killer could foresee an American playboy and a Scottish bean nighe tracing his victims to Finsbury Park Station.