Caillou At The Beach is an episode from Season 1. The episode takes place right after the episode Caillou Rides an Airplane.
Caillou and his family are on vacation. It the first time that Caillou has ever been to the beach. Caillou's Mommy makes him wear sunscreen and then finds a place on the beach for their umbrella. His daddy then takes him into the ocean and it is cold. A wave comes in and they both get saltwater in their mouths.
It is soon time for lunch. Caillou likes having a picnic on the beach. Then his sandwich gets sand in it. Suddenly, a bird comes by and takes the sandwich. Caillou is mad and follows a crab into a tidal pool. In the tidal pool, there is a seahorse.
His mommy then wants to build a sandcastle. Caillou shows Rosie how to make it. The tide then comes in, and Caillou's Daddy says that it's time to go. Then the sandcastle is ruined by the tide, so Caillou will have to come tomorrow to build another one. Then Caillou says that they'll come back "the next day, and the next day, and the next day, and the next day".