Leo has a hamster named Buddy. Caillou thinks that Leo is lucky to have him. Leo's going to be away from home for a while, so Caillou gets to take care of Buddy while Leo is away. Leo shows Caillou how to hold Buddy and reminds him to be gentle. Leo feeds Buddy a carrot and Caillou is surprised to see Buddy appear to eat the entire thing very quickly, but Leo explains that Buddy is actually hiding the carrot in his cheek pouches. The time finally comes for Caillou to take Buddy home. Leo's Mom gives Caillou a list to give to his Daddy. At home, Daddy makes sure that Gilbert stays out of Caillou's room so he can't get to Buddy. They check his food and water and then Daddy suggests that Buddy be left alone for a while because he's sleeping. So Caillou goes off to play with some blocks, but he gets bored and ends up taking Buddy out of his cage, even though Buddy was still sleeping. Buddy scurries all over Caillou and then runs off and into a small crack between one of Caillou's dressers and the wall. Caillou can't reach him and runs off to get Daddy, but when he gets back, Buddy is gone. Daddy and Caillou go on a hunt for him, but first Daddy locks Gilbert up in his cage so he can't go after Buddy. Eventually they hear Mommhy shouting out from the kitchen. They go in there and find her standing on a chair. It turns out that Buddy is underneath the refrigerator. So Caillou gets a carrot and uses that to lure Buddy out. Buddy is returned to his cage for a chance to really get some rest. When Leo arrives back from his trip, Caillou tells him all about what happened and how he used the carrot to lure Buddy out.