As Christmas approaches, there's a chill in the air-not from the weather, but from the mysterious goings-on in Stonybrook. Someone is breaking into houses in Kristy and Abby's neaighborhood. Meanwhile, Mallory is struggling to help a woman who has suddenly appeared in town with no identification and no memory. In New York City, Stacey and Claudia are being followed. And someone is leaving very odd, unsettling gifts at Stacey's door. It looks as if the Baby-sitters are in for a very scary Christmas!