The episode, "Olive Muddle" is episode 12 of season 5 of the Caillou series.
The episode starts with Caillou and Rosie looking out the window, waiting for Grandma. Boris exclaims that Grandma has a promise to bring over something special to eat. Rosie sees Grandma and the kids run to the door. Grandma wishes best of luck to Doris and Boris who are going golfing to the day, and says her grandchildren are in good hands. Doris and Boris head out, and Grandma reveals the special treat: olives! She exclaims she went to a special cooking class and learned all about the food. She gets out Italian olive bread, and Caillou observes the olives look like chocolate chips. Rosie appeared to enjoy the bread, and Caillou assumes he'll like it too, but once he tastes it, he finds out that he does not care for the taste of olives. He doesnt want to hurt Grandma's feelings, so he lies and says he liked it. That is not the only olive treat, there are more in store! "More?" Caillou responds as Rosie cheers. Snack time includes olive dip and crackers, which Caillou smears on his face to avoid the dip. For dinner, Grandma serves pizza, which both Caillou and Rosie are excited about (that is, Caillou is until he sees the olives). Again, he was afraid he would hurt Grandma's feelings by telling her he did not care for olives. Then, he had a great idea! He put some of the unwanted olives in Rosie's crayon box, some in his napkin, and gave some to Gilbert which he had to retrieve from him when Grandma wasn't looking! Caillou finishes the olive-less pizza, and Grandma says, "I'll have to make more olive treats!" She announces she made dessert, which Caillou imagines is a huge olive cake! He puts his foot down, and says "I don't like olives!", and apologizes. Grandma is confused why Caillou didn't tell the truth, and Grandma explains why she isn't upset. The trio enjoy oatmeal cookies, then Doris and Boris arrive home, while the kids are coloring. Boris takes out a crayon to write Rosie's name on her picture, and finds an olive attached to the crayon. Caillou says, "Oops! Looks like I have some tidying up to do!" The episode ends with the summary that Caillou can be honest with everyone.