The Magnificent Showboats follows the farcical adventures of Apollon Zamp, owner of the showboat Miraldra's Enchantment, and his troupe of acrobats, magicians and actors. Zamp is invited by the King of Soyvanesse to travel up the river Vissel to the distant city of Mornune, there to participate in a contest. A rich prize awaits the showboat captain who stages the most spectacular performance and succeeds in entertaining the king.