Most good stories start with a fundamental list of ingredients: the initial situation, conflict, complication, climax, suspense, denouement, and conclusion. Great writers sometimes shake up the recipe and add some spice.
Initial Situation
When the manciple of the local university becomes ill, Symkyn, the miller, takes the opportunity to steal even more flour than usual from it, prompting two clerks, John and Aleyn, to journey to the mill next time to prevent it from happening again.
All of the elements for a really good conflict are in place with this set-up: Symkyn's more blatant than usual cheating of the university prompts John and Aleyn to boast that they'll prevent him from doing it again; having publicly announced their intention, they can't back out now. But we know Symkyn's a proud guy, not to mention supremely unethical. Will he figure out a way to cheat the students despite their stratagems?
Conflict
John and Aleyn announce their intention to watch the corn being ground. Symkyn promises himself that he'll manage to cheat them anyway.
Symkyn makes the conflict between himself and the clerks totally clear. He also clarifies that he sees the conflict as one between the learning of clerks and the common sense street-smarts of peasants like him.
Complication
The clerks ask to spend the night at Symkyn's house, and bed down with the family in their shared sleeping quarters.
Just when we thought the conflict was over and Symkyn the clear winner, John and Aleyn decide it's too late to go home tonight. The fact that they bed down in the family's shared quarters, in close proximity to Symkyn's wife and daughter, and that they've got a bone to pick with Symkyn, leads us to suspect that something naughty will soon be afoot.
Climax
Aleyn has sex with Symkyn's daughter. John has sex with Symkyn's wife.
Aleyn and John get "payback" for their stolen corn. Everything in the story has been leading up to this, from numerous double-entendres in the tale's scenes and language to the opportunity presented by those shared sleeping quarters. When Aleyn calls sex with Malyne "esement," meaning both payback and physical release, we know that the sex is pretty much a done deal.
Suspense
John moves the cradle to his own bed to get Symkyn's wife into it. As Aleyn creeps back to their bed in the morning, he's confused by the misplaced cradle and crawls between the sheets with Symkyn. Mistaking the miller for John, Aleyn whispers to him that he's just had sex with Malyne.
The minute John moves that cradle, we know disaster's about to strike. Sure, it causes Symkyn's wife to hop into bed with John, but since Aleyn doesn't know a thing about it, he's sure to hop into the wrong bed, too! Sure enough, he does, and to make matters even worse, he brags about sleeping with Malyne to the last person he should. Now the reader is left wondering how Symkyn will react to this slight to his daughter's honor.
Denouement
Symkyn leaps out of bed in a rage, and he and Aleyn go at it. His wife, mistaking him for a clerk, strikes him over the head with a staff. Aleyn and John beat Symkyn unconscious.
The tensions that have been brewing between the characters, and the suspense that has been slowly building, get released here in physical violence. Finally, the rivalry between the clerks and the miller, which was never stated outright but always implicit, is out in the open.
Conclusion
John and Aleyn leave the mill, taking all their flour – including the part that John stole – with them. The narrator explains that "thus was the miller repayed."
John and Aleyn are the clear winners in this conflict, getting not only their full amount of corn, but also something "extra" in the sex they have with the miller's wife and daughter and the beating they give Symkyn. The narrator draws a moral from the story, saying that this punishment served Symkyn right for cheating his customers.