Gilbert and Sullivan change the characters, which Sullivan found artificial and lacking in "human interest and probability", as well as being too similar to their earlier opera, "The Sorcerer". As dramatised in the film "Topsy-Turvy", the author and composer were at an impasse until 8 May 1884, when Gilbert dropped the lozenge idea and agreed to provide a libretto without any supernatural elements. The story focuses on a "cheap tailor," Ko-Ko, who is promoted to the position of Lord High Executioner of the town of Titipu. Ko-Ko loves his ward, Yum-Yum, but she loves a musician, who is really the son of the
The Mountebanks work was released in 2018. The story of the opera revolves around a magic potion that transforms those who drink it into whoever, or whatever, they pretend to be. The idea was clearly important to Gilbert, as he repeatedly urged his famous collaborator, Arthur Sullivan, to set this story, or a similar one, to music. For example, he had written a treatment of the opera in 1884, which Sullivan rejected, both because of the story's mechanical contrivance, and because they had already produced an opera concerning a magic potion, "The Sorcerer" (1877); Sullivan felt that the story lacked "human emotion".