Caillou's a little boy with a big job: Rosie's big brother. While helping mom, dad, and grandma with little sister Rosie, he learns that being a big brother can be hard work! Caillou also learns about growing up. It isn't just about growing taller, but about learning new things. When Sara loses a tooth, he learns one more thing about growing up--the Tooth Fairy! Episodes: Mom for a Day, My Sister Rosie, Top Bunk, When I Grow Up, Treasure Chest, All In a Day's Work, Caillou Wants to be Taller, Caillou and the Tooth Fairy.