As the fog clears in the opening scene, we meet our hero, King Arthur, and his faithful servant, Patsy.
Arthur's on a quest to round up some knights for his court at Camelot. Unfortunately, this isn't as easy as he'd hoped. His journey is impeded by a skeptical guard, a politically conscious peasant unwilling to submit to Arthur's divine authority, and a knight in black who doesn't understand the meaning of defeat.
Yeah, get ready for some slapstick.
Arthur meets his first knight, Bedevere, when he witnesses Bedevere's uncanny skill in solving the question of whether or not a woman is a witch. With that, we fast-forward to Arthur's completed cadre of brothers in arms: Sir Robin, Sir Galahad, and Sir Lancelot. They're about to go to Camelot when Arthur realizes that it is "a silly place."
So they don't.
But just before we're left without a plot, God descends upon the company and orders Arthur to seek the Holy Grail. They journey to a castle where they're met by a rather rude French guard who goads the company until they attack without success. Then they pull the old Trojan Rabbit trick...also without success.
They're really not very good knights.
So they decide to split up. Robin meets a giant with three heads that argue among themselves about whether to kill him. Robin runs away and is branded a coward. Galahad the Chaste enters Castle Anthrax and, although strong at first, eventually begins to succumb to evil temptresses until Lancelot "saves" him at the last moment.
Arthur and Bedevere come across the Knights Who Say Ni. They demand shrubbery which Arthur and Bedevere miraculously find and give to the Knights, who then demand another. Arthur refuses and defeats the knights by saying the word they cannot hear… whatever it is.
Oh, and at some point, a modern-day historian giving a lecture on the Middle Ages is killed by a knight in a ride-by.
What can we say? It's British humor.
Meanwhile, Lancelot is off slaying wedding guests on his way to rescue a damsel in distress who turns out to be a lad wanting to escape his wedding. Lancelot joins up with the rest of the crew and they run into an Enchanter named Tim. Tim tells them about a cave guarded by a terrible beast. The beast turns out to merely be a cute little bunny rabbit, who proceeds to viciously kill several of them.
Luckily, they have the Holy Hand Grenade and blow up the bunny, allowing them to investigate the cave. That is, until they're again almost killed by a giant animated beast that's only defeated when the animator has a heart attack. How meta.
Continuing their noble quest, the Knights of the Round Table arrive at the Bridge of Death, which spans the Gorge of Eternal Peril. The Bridgekeeper makes them answer three very random questions. Arthur, Bedevere, and Lancelot make it across, but Lancelot disappears.
Arthur and Bedevere continue on and find the castle which supposedly has the Grail, but it's already been occupied by the same rude Frenchmen as before. Art and Bed fall back and summon an army seemingly from thin air. Just as they begin to charge the castle, they're stopped by policemen investigating the murder of the historian. The historian's widow IDs Arthur as the murderer, and he's taken into custody and thrown into the squad car.
The End...wait, what?