Escaping from a distasteful marriage, Nanki-Poo, the son of the Mikado, arrives in the town of Titipu - disguised as a musician. He has chosen Titipu because a beautiful girl, Yum-Yum, with whom he has fallen in love, lives in the town. A desire to marry Yum-Yum, however, is not enough. Nanki-Poo has to contend with her guardian, Ko-Ko, the Lord High Executioner, who has every intention of marrying Yum-Yum, himself. Problems are compounded when the Mikado, accompanied by Katisha, Nanki-Poo's jilted bride, also arrive in the hitherto peaceful town of Titipu

As a young child, Frederic had been apprenticed to a pirate by mistake when he should have been apprenticed to a pilot. Now, having reached his 21st year, Frederic's indentures are at last over and he happily leaves the service of the pirates. When Frederic meets the beautiful Mabel, one of the many daughters (or wards in Chancery) of Major-General Stanley, they fall in love and decide to marry. However, complications arise when the pirates decide to marry the rest of the Major-General's daughters, themselves - and Frederic's birthdate turns out to be not all it seems.

Strephon, a shepherd (the son of a Fairy, Iolanthe, and a mortal), is in love with Phyllis, a shepherdess. He wants to marry her, but, although Phyllis also loves Strephon, she has a dilemma - she is so beautiful that all of the House of Lords, as well as her guardian, the Lord Chancellor, are also desirous of marrying her. There are many complications - including the peers being threatened by the Fairies - before a happy conclusion is reached by all.

In a breach of promise case, the Learned Judge and Jury are somewhat smitten by the pretty Plaintiff's charms, and the Defendant is hard pressed to explain that indeed he loved this girl once, but fell in love with another. Despite his suggestion that he marry both women, the Learned Judge has his own solution... he will marry the Plaintiff himself!