London, 1821. Former spies Malcolm and M矇lanie Rannoch have been friends with Bow Street runner Jeremy Roth since they all met in the intrigues of the Peninsular War. Now settled in London, they frequently collaborate. On a chilly night, an urgent summons from Roth takes Malcolm to a tavern in the slums of Seven Dials. He finds Roth standing over the body of a murdered woman. Malcolm offers his assistance with the case, but Roth says Malcolm must investigate alone. When Malcolm asks why, Roth replies-because this is my wife.

Malcolm and M矇lanie plunge into the secrets of Roth's estranged wife Allegra. Why did she disappear from England? Where has she been for five years? And why did she return now to the husband she abandoned? Their investigation is a race against time as another Bow Street runner is all too eager to arrest Roth for the murder. And though Malcolm and M矇lanie are both convinced Jeremy Roth is not a killer, his story keeps changing.

Secrets are nothing new for the Rannochs. But this investigation will force them to question everything they thought they knew about some of those closest to them. And to re-examine the secrets at the heart of their own marriage-before someone else they love falls victim...