Shadowdance: The Darkest London Series: Book 4

Life has been anything but kind to Mary Chase. But the Society for the Suppression of Supernaturals has given her purpose. Now she's been tasked with catching a vicious murderer dubbed the Bishop of Charing Cross. But someone is already on the case-and the last thing he relishes is a partner.
Only someone who lives in darkness can find it.

Jack Talent has been alone with his demons for many years.
He never expected to have the willful Mary Chase assist him on the Bishop case. Their age-old rivalry reaches new heights-even as their desire for one another reaches a fever pitch. Though he aches to bring her close, Jack's dark secrets are a chasm between them. With dangerous enemies closing in, Jack must find the strength to face the past . . . or risk losing Mary forever.