Caillou's family goes to the beach. It's Caillou and Rosie's first time. Caillou goes into the water with his Daddy. He has a picnic with his family, but a seagull steals his sandwich. He follows a crab to the sea and sees lots of sea creatures. Then, he builds a sand castle with his Mom. Finally, the tide comes in and they have to leave for the time being, but they'll come back the next day (and the next day and the next day...) (thetvdb.com)