The opera is set in the fictional Japanese town of Titipu. The plot revolves around Nanki-Poo, the son of the Mikado of Japan, who has been exiled for falling in love with Yum-Yum, a ward of Ko-Ko, the Lord High Executioner. Nanki-Poo disguises himself as a minstrel and enters Ko-Ko's service, hoping to marry Yum-Yum. However, Ko-Ko is scheduled to be executed unless he can find someone to execute, and he decides to execute Nanki-Poo. Nanki-Poo is saved when Katisha, an elderly lady who is in love with Nanki-Poo, appears and claims him as her husband.
The Mikado is one of the most popular and successful of the Gilbert and Sullivan operas. It has been performed thousands of times around the world. The opera is known for its witty humour, beautiful music, and colourful costumes.