It's summer...and you've agreed to baby-sit Mr. and Mrs. Harper's little girl, Katie, three days a week. You've never baby-sat before, but they have offered you $7.50 an hour--an offer you can't refuse. All your friends are jealous. Baby-sitting a two-year-old should be a snap, right? Wrong. There's something strange about Katie. When her parents are around, she's a perfect little angel. But when they leave, Katie turns into something frightening. Something scary. Is it all in your head? Or is Katie evil?