People go missing every day in the Scottish capital, where Luke Calvin treads the tightrope between the law and order of the police and the harsh realities on the streets. Existing in his own personal grey area and plying his trade as a private investigator in the shadows of Edinburgh, he operates at the behest of the ""office"" - nothing more than some semi-official voices on a phone and a steady paycheque for doing the work that they can't be seen to do. When a local magistrate requires his services to locate an errant son, Luke has to rely on every contact he has made on both sides of the law to find his man before time runs out. Family ties, the bonds of friendship, and the tether of a man to his employer are all tested to the limit and beyond as he does his best to stop another name from ending up as a footnote in the list of those that have been lost in the shadow of the castle.