Caillou goes up to the attic with Mom and finds a box containing a teddy bear and a music box. Mom gives the bear a bandanna, transforming him into a pirate bear. Caillou decides he likes the bear more than the music box. Since Caillou has made his choice, Mom decides to give Rosie the music box. When Caillou realizes that the music box was still working he wants it back. Caillou and Rosie find a way to both get to play with the music box and the pirate bear.