The year is 1908, and a troupe of vaudeville performers has arrived in sleepy Muskegon, Michigan to spend the summer in nearby Bluffton. Young Henry Harrison is fascinated with the animals and performers, and thinks this is about the most exciting thing since baseball. So Henry has a few months to ogle the elephant and the zebra, the tightrope walkers, and a slapstick performer his own age named Buster Keaton, who is also a master prankster and loves to play baseball. The show folk say Buster is indestructible; his father throws him around as part of the act and the audience roars, while Buster never cracks a smile. Henry longs to learn to take a fall like Buster, "the human mop, " but Buster just wants to play ball with Henry and his friends.