"To Seduce an Angel" by Kate Moore

This is the final book in the Sons of Sin trilogy (I posted about the other two, "To Tempt a Saint" and "To Save the Devil," in 2011).  Kit Jones is the youngest son of an infamous London courtesan and her late husband, the son of a duke.  Kit was rescued four years ago from living on the streets after being kidnapped from his family as a young teen.  He's now been named the Marquess of Daventry, much to the consternation of his evil grandfather and dangerous cousin, who were behind the kidnapping.

Daventry hires Emma Portland as a tutor for his charges, youngsters who once lived on the streets of London with him.  But she has been blackmailed by his grandfather to spy on Daventry, something that she finds harder and harder to do as she discovers that they have much in common and begins to fall in love with him.

I enjoyed this story with its two unusual leads.  They're both only 20 but lived very harsh and difficult lives in their teens, and Emma is still living that life of fear.  Several twists in the plot kept me interested, as well as the author's unusual turns of phrase.  284 pages.