Hanging Hill / Mo Hayder.

What if you found yourself divorced and penniless? With no skills and a teenage daughter to support? What if the only way to survive was to do things you never thought possible, to go places you never knew existed a These are questions Cal has never really thought about before. Married to a successful business man, she's always been a bit of a dreamer. Until now. Her sister Zoe is her polar opposite. A detective inspector working out of Bath Central, she loves her job, and oozes self-confidence. No one would guess that she hides a crippling secret that dates back twenty years, and which u if exposed u may destroy her. Then Cal's daughter gets into difficulties, and Cal finds she needs cash u lots of it u fast. With no one to help her, she is forced into a criminal world of extreme pornography and illegal drugs; a world in which teenage girls can go missing. Two sisters intent on survival. Until one does something so terrifying that there's no way back again.