Merry Christmas, Gull Island! Neeve, Phoebe, Kate, and Hillary—the 12-year-old Callahan cousins—are back at their grandmother Gee's rambling seaside estate for Christmas break! When the girls camp out at a whaling museum they stumble upon a mystery they can't ignore. Phoebe takes the lead as the girls join forces to solve an island mystery. Plus, what will the girls get Gee for Christmas? Hint: It's warm and fuzzy and needs to be fed!