The man is newly retired DCI Woodend, and the woman is Sergeant Monika Paniatowski, who will replace him. They have sneaked away from his retirement party. Woodend is waiting for the train that will take him to his retirement villa in Spain. Paniatowski is already missing him; he has been her boss and mentor, and she's dreading his retirement. She teases that it's a miracle he actually made it to retirement, and Woodend smiles and says that's less remarkable than his promotion to Chief Inspector in the first place. He says he did it "by arrangin' to have somebody killed." She asks him to tell her about it, so he does.
At the crime scene, Woodend is disgusted by the language the doctor and the constable use to refer to the murdered girl, who is black. They suggest that the murder will be low in priority for the Met, and their predictions are fulfilled and more. First, Woodend's superior, a lazy and irascible DCI named Bentley, assigns him to head this investigation, a first for Woodend. Then, an anonymous call to Woodend's home warns him that "if yer know what's good for yer, yer won't do that job too thoroughly." Woodend's investigations yield some surprising facts about the murdered girl, Pearl Jones; when Woodend reports these facts to DCI Bentley, he yanks Woodend from the case and assigns him to the death of a criminal at the rough Waterman's Arms.
Fatal Quest, the last in the series, but detailing Woodend's first case, is a well-written English police procedural, full of wonderful characterizations and ironic humor (Woodend's wife refers to his "sweatin' over a hot criminal all day" when he arrives home). It's more than a simple story of how Woodend tracks down a murderer and becomes a DCI. It's a look at love in its many different forms and the heartache and havoc it can cause. It's a depiction of London five years after the war when bombed-out sites remain and people are scrabbling. The black market opened up new ways for criminals to make a living. Overt racism and corruption stain the Met, and some Met officers argue that organized crime is beneficial because powerful gangsters help keep crime under control. Against this backdrop, it's good to watch the decent Woodend work his first case. Then, in the first book of the series, 1998's The Salton Killings, Diane Thorburn is only the latest in a series of schoolgirls to be killed in 1950s Cheshire, and DCI Woodend will investigate. There are 18 books between these two.