A Christmas calendar for a cause turns into so much more. Dean always goes after what he wants, but when he steps in to help his best friend, modeling for a December countdown to Christmas calendar, a photo shoot for a good cause, he runs into Leah - his best friend's little sister. Despite being warned to stay away from her, Dean finds himself uncharacteristically flustered and distracted by the firecracker that is Leah. Leah has worked hard for her position in her company and is determined to make her mark with the Christmas fundraiser, but with Dean's presence stirring up her long-held feelings for her secret crush, she's finding it harder and harder to stay focused. He's a player and her brother's best friend. She's off-limits, his best friend's little sister. Dean and Leah struggle with temptation, both trying to decide if they should take a chance on each other. Will Dean and Leah give in to temptation this Unforgettable December?