So, the story begins: to the court of the legendary King Arthur, where the brave and noble knights gather, there is a girl on a mule. The beauty rides “completely without restraint” and weeps bitterly. Noble ladies and knights send Seneschal Kay to find out what is the matter. Soon, Kay returns and reports: the girl is sad that her mule has no reins, and she is looking for a brave knight who agrees to find this reins and return to her. And if there is one and will fulfill her request, she is ready to become his humble wife.

Delighted with the beauty of the lady, Kay asks for permission to accomplish this feat. Ready to follow the reins at least to the ends of the world, Kay wants to get a kiss from the lady in front of the road. However, she refuses him: first a bridle, and then a kiss. Losing no more precious time, Kay sits down on a mule, and Kay confidently cowards along a familiar road. Soon the mule turns into a forest full of lions, leopards and tigers; with a loud roar, the beast rushes "to where the knight went." Cursing everything in the world, the unlucky seneschal only thinks about how to quickly get his feet out of here. Out of reverence for the mistress of the mule, predators, following the eyes of the rider, retreat into the thicket.

The forest ended, the mule rode out onto the plain, and Kay perked up. However, he does not rejoice for long: the mule enters the gorge, where "snakes, tarantulas and spiders" swarm at the bottom, whose stinky, foul breath, swirling like black smoke, so frightens Kay that he is ready to return to the forest in horror to wild beasts. Finally, this obstacle is behind, now Kei is waiting for a stormy stream, over which you can only cross the bridge. The seneschal does not stand and turns back; thanks to the mule, he passes unscathed of all the reptiles and the beast, and finally drives up to the Arturov Palace.

Upon learning that he had not brought the reins, a girl in grief tears her hair. Touched by her grief, the knight Gauvin asks for permission to bring him a rein. Hearing his words, the girl joyfully kisses the knight: her heart tells her that he will bring the bridle. Meanwhile, Seneschal Kay, "grieving with his soul," leaves the yard; without fulfilling the knightly deed taken, he does not dare to appear before King Arthur.

The mule drives Gowen along the same paths as Kei. Seeing the familiar mule and his rider, the brave Gauvin, the animals run out to meet them. Gauvin realizes that, frightened by the beast, Kay broke the word given to the lady. Gauvin himself fearlessly goes on and with a smile on his lips passes the gorge of horror, and the stench, at the bottom of which bastards swirl.

On a narrow plaque, the knight fearlessly crosses the seething stream and drives up to the castle, which rotates like a mill wheel. The castle is surrounded by a deep moat with water; around the moat stands a picket fence decorated with human heads; one pole of this terrible fence is still free. But the knight does not shy of the soul. Having driven onto the bridge, Gauvin bravely rushes forward and enters the castle at the cost of only half the tail of the mule, which "hangs at the gate". Everything is empty and quiet. In the courtyard he is met by a silent dwarf; following him, Gauvin encounters a huge hairy villein with an ax around his neck. Villan warns the knight that getting to the coveted reins will not be easy; but a warning only ignites the hero’s courage. Then villeinas cares about the knight, takes him to the house, serves dinner, makes a bed, and before going to bed offers a game: first, Gauvin will cut his head off, and then he will goven. The knight agrees, cuts off the head of the villana, he takes it under his arm and leaves, promising tomorrow to appear behind Gauvin's head.

In the morning, faithful to his word, Gauvin puts his head on the block. But it turns out that the shaggy giant only wanted to scare him. The terrible-looking villan becomes a faithful servant of the knight and equips him to fight with ferocious lions. Seven shields are broken by predators, but nevertheless the knight defeats them. Gauvin is ready to get a bridle, but this is only the first test. When the knight rested and changed his armor, Villan leads him to the hall where the wounded knight lies. According to custom, this knight fights with everyone who comes to the castle for a bridle. A knight defeats an alien, cuts off his head and puts it on a stake near the moat. If the alien defeats the knight, then he will have to chop off his head and take his place himself. Gauvin, of course, defeats the knight of the castle, but generously keeps his head on his shoulders. Now the shaggy villan will bring him a bridle, Gauvin thinks. But Arturov Knight is waiting for a new test: Villan leads him to two fire-breathing snakes. With a mighty blow, Gauvin cuts off both reptiles of the head.

Then the former dwarf appears to Gauvin and, on behalf of his mistress, invites the knight to share a meal with her. Gauvin accepts the invitation, but, not trusting the dwarf, demands that he be accompanied by a faithful villan. Following his escort, the knight comes to a beautiful lady. Enthusiastic about his courage, the lady invites Gauvin to the table. Villan and the dwarf serve them, the lady cordially treats the hero. When the meal was over and the servants took away water for washing their hands, Gauvin asks the lady to give him a bridle. In response, she declares that he fought for her sister, and therefore she is ready to give him all of herself, so that he becomes master of both her and her fifty castles. But the knight courteously replies that “about the news that happened” he is obliged “to bring to the king sooner”, and therefore he must immediately set off on his way back. Then the lady points him to a silver nail, where a precious reins hang. Gauvin takes off his reins, says goodbye to the lady, and Villan brings him a mule. The lady asks the villan to stop the rotation of the castle so that the knight easily leaves its walls, and he willingly fulfills her request,

Driving past the gate, Gauvin stares in surprise at the jubilant crowd: when he entered the castle, there was not a soul in it. Villan explains to him: before all these people were hiding in a cave because they were afraid of wild animals. Only those who are brave sometimes go to work. Now, when Gauvin killed all the predators, they rejoice in the light, and their joy has no limit. Villan's speeches are a great joy for Gauvin.

Here the mule again runs across a narrow board, turns into a stinking gorge, drives into a dense forest, where all the animals again jump out to meet him - kneel before the valiant knight. But Gauvin has no time - he hurries to Arthur's castle.

Gauvin enters the meadow in front of the castle, the Queen and her retinue notice him from the windows. Everyone rushes towards the brave knight, and the lady who arrives is most rejoiced: she knows that Gauvin brought her a rein. Having awarded the knight with a kiss, she thanks him for the feat. “And then Gauvin told her adventures without embarrassment”: about the forest, about the furious stream, about the wonderful palace, about the dwarf and about the villein, about how the lions were killed, how the famous knight was defeated, how two snakes were struck at once, about the meal and a conversation with her sister, about the jubilation of the people in the castle.

After listening to Gauvin's story, the lady asks for permission to leave, although everyone, including the king himself, persuades her to stay and choose a lord among the knights of the Round Table. But the lady stands her ground: she is not free to stay, no matter how much she wants. Sitting on a mule, she, abandoning the escort, jumps back to the forest. On this story "about a girl on a mule, who suddenly left the palace, here finds its end."