Ten-year-old Vanessa is used to teachers at Book Smith Elementary being a little strange. Mrs. Charlston, the homeroom teacher, likes to pick her nose, while Mr. Pickle, the math teacher, has a serious drooling problem. But compared to the mysterious Ms. Gavin, her other teachers are pretty normal. Ms. Gavin has a thing about cabinets. Usually, Vanessa is free to get what she needs from teachers' cabinets-construction paper, crayons, anything-but not around Ms. Gavin. Vanessa has tested her before, lingering near Ms. Gavin's cabinets. Her teacher gets nervous even when someone just wanders in the area of her cabinets. So what is Ms. Gavin hiding? What on earth could be in those cabinets? Nothing can keep Vanessa's curiosity in check ... even possible detention. It's a grand mystery, but she can't solve it alone. She finds an unlikely ally in eight-year-old Johnny, who's a lot wiser than he lets on. Together, they can open the doors to Ms. Gavin's secret. But what if her secret is scary? And what if the adventure is dangerous?