"What is Lag Ba'Omer?" Sadie and Ori ask their grandfather, who sends them off on a mission to solve the mystery. They learn the surprising history and traditions behind the holiday, and invite their friends and family to a Lag Ba'Omer picnic and celebration. The fourth title in the "Sadie and Ori" Jewish holiday series including Sadie's Sukkah Breakfast, Sadie and the Big Mountain, and Sadie's Almost Marvelous Menorah.