Private investigator Jasmine Sharp's father was murdered before she was born, and her mother went to self-sacrificing lengths in order to shield her from the world in which he moved. Since her mother's death, all she has been able to learn is his first name - and that only through a strange bond she has forged with the man who killed him: Glen Fallan. But when Fallan is arrested for the murder of a criminal her mother knew since childhood, Jasmine is finally forced to enter his domain: a place where violence is a way of life and vengeance spans generations.

Detective Superintendent Catherine McLeod has one major Glaswegian gangster in the mortuary and another in the cells for killing him - which ought to be cause for celebration. Catherine is not smiling, however. From the moment she discovered a symbol daubed on the victim's head, she has understood that this case is far more dangerous than it appears on the surface: deeper than skin, darker than blood; something that could threaten her family and end her career.

As one battles her demons and the other chases her ghosts, these two very different detectives will ultimately confront the secrets that have entangled both of their fates since before Jasmine was even born.