The siren song of an unsolved murder case beckons an ex-cop back into detective work.

Michael McLaren tries to convince himself that he is perfectly happy repairing dry stonewalls in Derbyshire, a make-do career after resigning his job in an eddy of anger, disgust and an overwhelming sense of injustice. But when a murder victim's friend asks him to investigate a cold case, McLaren agrees, the chance to rectify a wrong and return to the work he loves too heady to ignore.

Marta Hughes, the murder victim, never returned home from a local casino where she won a purse-choking sum of money. Her body turned up ten days later and turned up the heat on the police investigation, but the time-lapse, lack of witnesses, and an untraceable bullet quickly turned the case cold. Now, one year later, McLaren sifts through the web of lies and veiled motives as impenetrable as boulders. Co-workers, friends, neighbors and even Marta's husband all seem to have reasons for wanting her dead. Reasons as varied as revenge for her damning silence to imagined infidelity.

Anger and motives overlap and raise more questions than McLaren can answer. In the midst of his investigation McLaren becomes entangled in his own mystery: anonymous late-night phone calls, a vanished hitchhiker, and a car crash threaten his life and sanity. Is Dena, his former fiancée, playing tricks on him, still angry over their broken engagement? Or does the killer fear McLaren's relentless law-skirting pursuit? But it isn't until McLaren unravels his personal puzzles that he discovers Marta's killer, a killer obsessed with old anger and new revenge.