It is about this time that Koko shows up, himself in tears. He is not at all happy about the situation - Nanki-Poo going to be living in his house, marrying whom Koko thinks of as “his” girl, eating all the food, and prepared to be very obvious in his expressions of affection toward Yum-Yum. Koko is also "upset" because he is the bearer of bad news. It seems that there was a law on the books, discovered by Pooh-Bah, that the wife of a condemned man is to be buried alive. Nanki-Poo never heard of such a thing, and there is a better than even chance that it was made it up by Pooh-Bah for Koko's benefit, to scare Yum-Yum from wanting to marry Nanki-Poo. It is a mean trick, but it works. It works too well. Yum-Yum now refuses to marry Nanki-Poo, and Nanki-Poo once again announces he will kill himself.

Seeing his best-laid plans ganging aft aglae, Koko deperately tries to coax Nanki-Poo into changing his mind, but by now Nanki-Poo has Koko's number, and has figured out what sort of man he really is. "Very well, then, behead me," he smiles, offering his neck then and there. After a very funny panic attack, Koko breaks down and confesses that he's not the kind of person who could even step on an insect, let alone harm Nanki-Poo or anyone else. He bursts into tears.

Ah, but there is still the problem of the Mikado! News arrives that the Emperor himself is approaching the city with a grand escort, and they had better do something quick. Suddenly Koko gets hold of himself and uses his wits, and decides there is no need to execute anyone as long as he can produce a Death Certificate with Nanki-Poo's name on it. In a moment of inspiration, somewhere between self-preservation and self-sacrifice, he orders Nanki-Poo to take Yum-Yum, marry her, and get out of town right away. Not too soon, for the Mikado arrives amid much pomp and cirsumstance.

He arrives accompanied by a majestic march (Sullivan based this tune on a genuine Japanese war march, also used by Puccini in "Madama Butterfly" ). He does not come alone. With him is Katisha, who is more aggressive that the Mikado himself - a woman who is clearly used to getting what she wants. His Majesty no sooner arrives, than Koko and Pooh-Bah show up to greet him, followed by Yum-Yum’s sister Pitti-Sing, who somehow got dragged along. By this time, Koko has actually turned the tables on Pooh-Bah and it is he who has learned how to manipulate the old rascal instead. They announce that there has been a rather grand and showy execution, and at the Mikado's request, regale him with an outrageous description of Nanki-Poo's beheading. The Mikado gobbles it all up cheerfully, even taking a monent (in Traditional performances) to flirt with Pitti-Sing, thus breaking his own law.

This has all been well and good, but it seems the Mikado has come about another matter entirely. Katisha has brought him there in search of his missing son, who goes by the name of "Nanki-Poo"--and whose name is on the Death Certificate!

The Mikado assures the terrified "beheaders" that he's not the least bit angry, and that everything is Nanki-Poo's fault anyway, but all the same there is a punishment for beheading the son of the Mikado. Something "humorous but lingering, with either boiling oil or melted lead". He'll settle the matter after lunch, in either case. Pooh-Bah doesn't want lunch.

Koko, Pooh-Bah and Pitti-Sing briefly fall to arguing among themselves, but Koko decides that Nanki-Poo will just have to “come back to life at once" , and let the rest of the chips fall where they may. Nanki-Poo, now married to Yum-Yum, is not about to come back to life, and with a grin, explains that it would be quite awkward now that he's married Yum-Yum, and Katisha still has a claim on him. And, he adds smugly, if he is beheaded, his wife must be buried alive.

Koko could kick himself. He could probably kick Pooh-Bah, too.

Nanki-Poo will be quite happy to come back to life for the sake of all involved--but as always, with a condition. Koko will have to take Katisha off his hands by marrying her himself.

Koko is aghast. Katisha is a very frightening person with a violent temper, she's no teenager, and she's not pretty! Not at all what he had in mind for himself! Pitti-Sing's assurances that the rest of her doesn't look so bad is hardly consoling. Nevertheless, he's trapped and he knows it. So bracing himself, he seeks her out in the garden, where she is singing a soleful and sorrowful song.

Katisha is heartbroken, wishing for death to take her any way it can. In that moment, she becomes suddenly a very sympathetic woman. For all her tough exterior, she is actually very vulnerable. That's when Koko shows up, begging for her hand in marriage with a stupid canned speech that only infuriates her. But somehow, a magic works in this famous scene that really cannot be described. Sadly, too many productions of "The Mikado" focus exclusively on the slapstick and the silliness - but much of that changed in the 1930's when Martyn Green, one of the most famous of all Koko's, sang the song "Titwillow" with a voice like pure honey, and melted the hearts of Katisha and every person in earshot. The scene has never been the same since. Despite the slapstick and silliness that ensues, the pair discover that they have a great deal in common, and the chemistry goes to work.

In any event, the Mikado finishes his lunch and is prepared to be entertained by the triple execution. He is greatly surprised (and disappointed) when Katisha shows up demanding "Mercy for Koko, mercy for Pitti-Sing, and mercy even for Pooh-Bah." The Mikado insists that since his son is slain, a punishment must be meted out. But his son has NOT been slain, and Nanki-Poo and his bride show themselves at last.

A furious Katisha turns on Koko for having tricked her, and even the Mikado demands an explanation. Koko gives him one. It is pure double-talk and nonsense, and the Mikado can't see the sense in it at all; but as Mikado, he could never admit before all these people that he doesn't understand. And so he smiles, "I see. Nothing could possibly be more satisfactory."

And so all's well that ends well. Nanki-Poo gets Yum-Yum, the Mikado has been pacified, and Koko and Katisha have found each other. As the Mikado himself would say, nothing could be more satisfactory for a perfect ending.