Behind the Veil by Kathryn Nolan

Just because the marriage is fake doesn’t mean the attraction is…

Delilah Barrett is a head-turning beauty on a quest for justice. The former cop with a checkered past has made a career of recovering stolen rare books with her private detective firm. She’s level-headed, smart, cool under pressure… and entirely unprepared for her new assignment.
When a centuries-old book worth an astronomical fortune disappears from Philadelphia’s Franklin Museum, Delilah is paired up with Henry Finch, a brilliant rare book librarian and celebrated academic.
Their orders: Go undercover as a married couple and recover the book by whatever means necessary.
Henry can speak four languages and wear a suit like he was born in Armani. But he’s never squared off against criminals. Never operated in this underground society of glamour and greed. And he’s certainly never pretended to be married to a woman who both dazzles and distrusts him.
Delilah’s keen instincts are her greatest gift, but her growing attraction to the sexy librarian is messing with her head. Every feigned caress, every for-the-audience kiss only heightens the seduction, building a fire that refuses to extinguish. As the danger intensifies, so does the temptation to let their fake desire become real. With a priceless artifact at stake, can this undercover couple learn to trust each other…before it’s too late?