All Bartleby has ever known is the life of a pet, but he dreams of being free to swim in deep, fast-moving water. When the boys he lives with watch a TV show called Turtles of the Mighty Mississippi, Bartleby is sure that the big river must be his real home. One day the youngest boy takes Bartleby for a swim in the nearby pond and forgets him there. Could this be Bartleby's chance to find his way home to the mighty Mississippi?