Jessi knows a secret language! She learned it from Matt Braddock, the BSC`s newest charge. Matt`s been deaf since birth, and he uses sign language to speak. Since Jessi is Matt`s baby-sitter, she`s been using sign language, too. Soon all the kids in Stoneybrook want to learn to sign . . . which keeps the Baby-sitters busy. Jessi`s the busiest of all: she working on another secret just for Matt. Will she be able to keep the secret and pull off her special event?