What Remains of Heaven — C.S. Harris

LONDON 1812.

When the controversial reform-minded Bishop of London is found bludgeoned to death in an ancient crypt beside the corpse of an unidentified man murdered decades before, Sebastian St. Cyr, Viscount Devlin, reluctantly agrees to help with the investigation.

To Sebastian's consternation, the last person to see the Bishop alive was Miss Hero Jarvis, a woman whose already strained relationship with St. Cyr has been complicated by a brief, unexpectedly passionate encounter. As his search for the killer leads him from the back alleys of Smithfield to the power corridors of Whitehall, Sebastian must confront the well-guarded secrets of his own family's past, and a devastating truth that could ultimately force him to question who -- and what -- he really is.