Rain, sleet, sun, and snow: Caillou is amazed by all the ways that weather changes. He's nearly in a state during a thunderstorm until Dad explains what thunder is (and how to tell it's going away). Caillou also makes the best of a rainy day by splashing in puddles. And when a winter storm hits, Mom and Dad make a scary blackout into a fun indoor camping trip, complete with sleeping bags and marshmallows! Mom is making one of her special snowman cakes, which means Caillou and Rosie have to go to the shop with her to get the ingredients. Then Caillou gets lost in the shop...but it all works out fine in the end. On another day, when Caillou's kite-flying plans are defeated by rain, he creates a pirate ship in his living room.