Caillou and Leo are playing with their rocket ships in the park. Rosie wants to help them build the space station but she accidentally wrecks it. At home, Caillou and Leo continue their space game and are thrilled when Mr. Hinkle gives them a cardboard box which they transform into a rocket ship. On a winter day, Dad and Caillou go over to Grandpa's with their skates. What was supposed to be a skating outing becomes a shoveling chore because of all the snow that has accumulated in Grandpa's driveway. Soon, Caillou finds a way to turn this into a game and has a lot of fun making snow castles. When Caillou and Rosie stay at Grandma and Grandpa's house, Grandpa uses pop bottles and a rubber ball to create a bowling alley in the backyard. Grandpa teaches Caillou to bowl, but when he is called inside, it's Caillou's turn to teach as he shows Rosie how to play. Caillou accidentally spills the rest of the milk before Rosie could get her cereal. She is very upset and Caillou suggests they go get some more milk at the corner store. At the street intersection, he shows Mom that he knows when it is time to cross safely. Caillou is excited when Miss Martin takes him and his friends to the park for some special activities. The rules are not easy to grasp, and the kids have a few comical mishaps in the process. Caillou discovers that you don't always have to win to be proud of yourself.