Game of Rogues (The Palace of Rogues, 9) by Julie Anne Long

One disastrous night. One devastating man. One diabolical proposition.
Gabriel Marchand ruthlessly fought his way up from the gutters of St. Giles to preside over London’s most exclusive gaming hell. Few dare cross him. But when a young earl gambles away his inheritance, Marchand makes an enemy: a woman with wit like a dagger and the softest eyes he’s ever seen.
Spend a night in his bed, and he’ll call off the debt. This is the offer he makes Guinevere Woodville, the earl’s sister, when she blames him for her brother’s disaster. She’d rather die, of course. But when their seething enmity gives way to sizzling attraction at The Grand Palace on the Thames, his offer haunts them. Soon it seems a matter of not if, but when.
It's not long before Ginny is facing two stark truths: the so-called worst man in London is the best man she’s ever known....and keeping him would mean losing everything and everyone else she loves. But Marchand has one final card to play…and losing everything is a risk he’s willing to take if it means a chance to love her forever.
A sexy, witty, and heartwarming tale, Game of Rogues has everything readers love about Julie Anne Long.
Tropes:

* enemies to lovers
* forced proximity
* age gap
* class difference
* partners in crime