His Mistress For A Week by Melanie Milburne

What happens in Monte Carlo… 

Ten years ago bookshop assistant Clementine Scott clashed spectacularly with architect Alistair Hawthorne. After the humiliation of that night she swore she'd never have anything to do with any man ever again, especially the arrogant Alistair! 

But when Clem's brother disappears with Alistair's stepsister, she isn't given a choice…she will be going with Alistair to Monte Carlo to retrieve them! Forced together for one week, they quickly realize that their enmity masks simmering, sizzling lust. They strike a deal: for one week only, all bets–and clothes–are off!