Leo tags along with Caillou and his family on a picnic. They play Knights and Dragons, have the picnic lunch, and play some more. Suddenly, thunder can be heard. Caillou and Leo pretends that it's a dragon's roar. Rosie's beginning to fret because of thunder, but Caillou and Leo pledges to protect Rosie. It then starts to rain, so they quicklly pack up and run for the nearest cave. They then proceed to keep Rosie occupied so that she ignores the thunder. The rain finally stops, and they all head home. The end.