Employed by a mother to babysit her 'perfect' son, The Optimist instead finds the overweight boy is a particularly unpleasant 10-year-old. Keeping him amused is no easy task, although when they visit the local circus The Optimist immediately falls in love with acrobatic Circus Girl and faces an adversary in strongman The Bull. Forced into performing with the acrobats, the clowns and on the high trapeze, he ends up being fired from a cannon by the cunning boy.