One Wylde Night. The Wylde Wallflowers, #1

The Wylde Wallflowers follows the Wylde twins, Felicty and Charity, along with their two cousins, Benedicta and Cordelia Wylde, as they join their eccentric aunt in London for one last season and one last chance to find husbands. But the girls have their own plans. they want adventure and excitement. They want to know what it means to live up to their family name and be Wylde!! Branded a wallflower along with her twin sister and her cousins, Miss Felicity Wylde has set out for London under the less than watchful eye of her eccentric aunt for one final season and one last chance to catch a husband.
But her sister has convinced her it's also a last chance for adventure. Goaded into attending a scandalous party, Felicity soon realizes her mistake. The women present are not ladies and men, though titled, are far from gentlemen. Closeting herself in the study, she hides there only to find herself trapped when a quarreling couple invade that space.  Lord Phinneas Merrick attended Lord Hadley's bacchanal as a means to an end.
His entire relationship with the notoriously hot tempered cyprian, La Belle Rose, had been a carefully crafted ruse to gain entree to a particular set and ferret out a blackmailer in their debauched midst. But when he discovers a shockingly innocent young woman hiding in the study where his entanglement with the infamous demirep has come to a crashing end, he knows that the first order of business must be to remove her from that house before the unthinkable happens.  But he can't wash his hands of her so quickly.
Not when the blackmailer has them in his sights. With her reputation and his honor hanging in the balance, Phin must convince her to a very public and very fake betrothal. There's only one problem. the longer their fake betrothal lasts, the more he desperately wants to make her his.