When Mr. Hinkle has a tree cut down, Caillou is afraid his swing tree is next! Dad decides to plant a new tree so it's a trip to the Nursery. Caillou learns about the differences between trees with needles and leaves. When Sarah gives Caillou an old toy horn, Caillou wants to blow it everywhere. But he quickly learns, not everyone wants to hear it all the time. But then, Dad brings Caillou to the park where he uses the horn to signal Sarah from afar. There is a time and place for everything! When Caillou dresses up like a mailman to deliver Mr. Hinkle's misdirected mail, he finds out Mr. Hinkle is sick. With help from Mom, Caillou makes up a get-well card and a big pot of chicken soup! When the park is closed for the day, Caillou's friends come over to his house to play. But when no one will share the sandbox toys, or the swing, Caillou wishes everyone would just go home. That is until Mom proposes a game everyone can play! When Leo forgets his brand new toy dinosaur in the park, Daddy and Caillou go looking for it, with no success. So Caillou, with Mommy's help, puts up a Lost and Found Poster, and then, finds 'Dino' at the Park Office Lost and Found!