The show is about a young boy named Caillou who lives with his mom, Doris; his dad, Boris; his little sister, Rosie; and his pet cat, Gilbert. Mr. Hinkle lives next door to Caillou's house and Caillou has a babysitter named Julie. In the first season, Caillou was 4 years old and wore a gray shirt in season 1, but later, he wore a yellow shirt in season 2, 3, 4, and 5. In season 4 and 5, Caillou started going to school. Many parents have criticized the show, due to Caillou's behavior.