Meet Holly Meredith. She's thirteen years old and in eighth grade. She has a little sister, Carrie, and a mom who calls her 'Holly Heart' because she was born on Valentine's Day. And she has a best friend, Andie. Now that Holly's mom has remarried, the house is bursting with kids. And Holly has to share her room with super-snoopers Carrie and Stephie, who are reading her ultra-secret diary! Meanwhile, Holly's dad invites Holly and Carrie to spend Christmas in California. Before they leave, Holly sees Jared giving a present to Paula Miller. Is Jared two-timing her again? Then Holly meets Sean, a cute California surfer. Should Holly just forget about Jared for the holidays?