Caillou has just got a new baby sister: Rosie (Mousseline to those who watch the French version). And his parents are ignoring him. This causes jealousy to ensue and ended with Caillou pinching Rosie. But his parents keeps cool and asks him on why he does that. Caillou admits that he doesn't like Rosie. His dad gives him a little pep talk, and he eventually copes with it. (thetvdb.com)