Leonard the lion lives in a small french zoo. He is the pride and joy of the townsfolk who regularly visit him at his comfortable and spacious enclosure. Each day, they joyfully greet Leonard. "Bonjour Happy Lion", they say. Leonard is very fond of all his kind friends.

The first person to greet Leonard each morning is the school teacher Monsieur Dupont. 

One day, the zoo keeper accidently leaves the door to the lion enclosure open!! Leonard goes out to explore the town and to visit his friends, but his presence terrifies the townsfolk who are only used to seeing him in his cage.

It is up the the zoo keeper's son, François, to return the happy lion to the safety of his enclosure before he is  captured by the fire service and the terrified townsfolk.