What starts off as a rather slow book develops into something interesting and enjoyable, if flawed in places. Lady Leticia Randall's husband is murdered, and her brother Justin is the only suspect - he was at the house that evening and fled the scene, leaving behind bloodstained clothing at his rooms. Yet Leticia knows Justin wouldn't have killed Randall, so she goes for help to one man she can trust: her former lover, Christian Allardyce, the sixth Marquess of Deane.

Christian and Leticia's history is complicated. Everyone thought they would marry, but twelve years ago Christian went off to serve King and country; while he was away Leticia married Randall. They've barely seen each other since, but Christian immediately comes to Leticia's aid.

As they begin to search for clues to the murder, they discover that Leticia really didn't know a great deal about her husband. As his private affairs are slowly unpicked, Leticia and Christian find that he was a man of many secrets, and that it will take more expertise than they have to get to the bottom of them. As they search for the true identity of Randall's murderer, Christian must try to convince Leticia to trust him and come to see that her place is by his side. But if they get too close to the truth of the murderer, might they not be risking their own safety?

The Edge of Desire is a surprisingly long book, and it moves quite slowly. The interest builds step by step as the layers in the plot are brought to light. After the first few chapters, the book settles into a rather uneasy format where we follow Christian and Leticia's murder investigation during the day then spectate on their bedsport at night - then on to the next day. As the narrative progresses, we spend more time on the investigation and less on the romance, and this is a marked improvement. As far as the romance side goes, it's understated in some ways as it was a rekindling of love between people who were incredibly close in their past. The characterizations of both Christian and Leticia are sparse at times - Leticia has a temper, we learn, and Christian is controlled and calm, but this reader never felt like she really got to know them.

Although I did enjoy The Edge of Desire (A Bastion Club Novel), I was dubious about some of the behavior of the main characters in this historical context. The lead couple spending pretty much every night in bed in each others' houses, with Lady Randall a widow of just a few days and still theoretically in deep mourning, seems too unlikely. Where are all the servants in a Marquess's house who would normally notice this kind of thing? It appears necessary for Laurens' romance side of the plot, but it's a bit too modern for the Regency period.

Despite this, the rest of the book is a good read, and I didn't guess the murderer until they were revealed at story's end. Although part of a series, this book works well on its own and sets up the reader for the next and last in the series, featuring Royce Dalziel.