Shot in Technicolor, the film stars Martyn Green as Ko-Ko, Sydney Granville as Pooh-Bah, the American singer Kenny Baker as Nanki-Poo and Jean Colin as Yum-Yum.

[3] At the court of the Mikado, the emperor orders his son, Nanki-Poo, to marry Katisha, an elderly courtier, or perish on the scaffold.

Later, in the town of Titipu, he inquires about his beloved, a schoolgirl called Yum-Yum, who is a ward of Ko-Ko (formerly a cheap tailor).

A gentleman, Pish-Tush, explains that when the Mikado decreed that flirting was a capital crime, the Titipu authorities frustrated the decree by appointing Ko-Ko, a prisoner condemned to death for flirting, to the post of Lord High Executioner.

Ko-Ko sends him away, but Nanki-Poo manages to meet with his beloved and reveals to her that he is the son and heir of the Mikado, in disguise to avoid the amorous advances of Katisha.

Pish-Tush arrives with news that the Mikado has decreed that unless an execution is carried out in Titipu within a month, the town will be reduced to the rank of a village, which would bring "irretrievable ruin".

As Yum-Yum prepares for her wedding, Ko-Ko and Pooh-Bah discover a twist in the law that states that when a married man is beheaded for flirting, his wife must be buried alive.

Aided by Pooh-Bah and his ward Pitti-Sing, he graphically describes the supposed execution and hands the Mikado the certificate of death.

The Mikado discusses with Katisha the statutory punishment "for compassing the death of the heir apparent" to the Imperial throne.