Elena Zoric is murdered, her body concealed beside a stream in North London. Her phone lies nearby, the last number dialled was to the woman who had rescued her from sex trafficking: Metropolitan Police Detective Inspector Grace Archer. Archer desperately wants to lead the murder investigation but her new boss, Chief Inspector Les Fletcher, makes it very clear its out of her jurisdiction.

Then the thirty-year-old remains of a woman are found in the attic of an abandoned house, the victim dying in similar circumstances to Elena Zoric. But Archer's North London colleagues have bigger priorities than the murder of 'a drugged-up prostitute.'

Archer needs answers. Who killed Elena? Why did she call Archer moments from her death? And what rules must she break to stop a killer in his tracks?