Christmas is both naughty and nice this year when a single dad and his best friend’s sister celebrate with some secret (steamy) romance and festive fun, perfect for fans of Maggie Knox and Lyssa Kay Adams.   Charlotte Calhoun has avoided Hayden Porter, her older brother’s sexy-as-sin best friend, ever since that mortifying night when he flat-out rejected her. She’s crushed on him forever, while he’s made it crystal clear he only sees her as a silly kid sister. Fine. Except this Christmas season, they’re thrown together at a snowy ski resort for her brother's bachelor party, complete with mistletoe, cozy fireplaces, and adjoining rooms. She can tell herself to get over Hayden, but holiday cheer is turning to holiday lust every time he is within ten feet of her.  Between being a full-time single father and his high-pressure college coaching job, a romantic relationship is off the table for Hayden. But every time he gets near Charlotte-all-grown-up, his feelings are anything but casual. So far, they have managed to keep their sexy times under wraps so that they don’t cause conflict on her brother’s big day. But a secret weekend fling is one thing. It’s two long weeks until the wedding, and hiding their growing feelings is going to take a Christmas miracle.