The wealthiest heiress of the season, Miss Lindsey Crompton finds detective work far more fascinating than social engagements—at least until she meets Thane Parker, the Earl of Mansfield. Thane is a paradox: a war hero and a cad, a wicked scoundrel and an indulgent guardian of his young ward. When Lindsey sneaks into his house to investigate his role in a series of murders, he blackmails her into a betrothal.

Thane has a secret life he keeps hidden from everyone, especially the infernally curious—and curiously alluring—Miss Crompton. Working with the Bow Street Runners, Thane is tracking a killer who may be one of Lindsey’s suitors. Even if their engagement is a ruse, the heat between Thane and Lindsey is undeniably real. And with a murderer on the loose, desire has never been so dangerous…