Hot winter nights / Jill Shalvis.

Most people wouldn't think of a bad Santa case as the perfect Christmas gift. Then again, Molly Malone, office manager at Hunt Investigations, isn't most people, and she could really use a distraction from the fantasies she's been having since spending the night with her very secret crush, Lucas Knight. Nothing happened, not that Lucas knows that - but Molly just wants to enjoy being a little naughty for once. Whiskey and pain meds for almost-healed bullet wounds don't mix. Lucas needs to remember that next time he's shot on the job, which may be sooner rather than later if Molly's brother, Joe, finds out about them. Lucas can't believe he's drawing a blank on his (supposedly) passionate tryst with Molly, who's the hottest, smartest, strongest woman he's ever known. Strong enough to kick his butt if she discovers he's been assigned to babysit her on her first case. And hot enough to melt his cold heart this Christmas.