The Black Sheep and the English Rose (Unholy Trinity #3)
Donna Kauffman

Finn Dalton is bad boy personified. Felicity Trent should know; she's a bad girl herself. But for Felicity, life as a jewel thief is almost as seductive as Finn is--and that's dangerous. Because for a girl like her one night is all she needs to get what she wants, anything more means trouble. Now, with both of them after the same thing--the rarest of treasures--who gets there first might be the last thing they want...