Marie tells of two knights who once lived as neighbors in Brittany. They were both married men of good repute and were friendly with each other, so when the first knight's wife gives birth to twins, he joyfully sends word to the neighbor, promising to name one after him. The neighbor is indeed happy to hear the news but his wife, who "was deceitful and arrogant, prone to slander and envy," says to all in the room that any woman who birthed twins must have slept with two men. Though her husband rebukes her for the ugly talk, their servants spread the gossip throughout the land, until everyone scorns the new mother for her supposed infidelity. Most grievous of all is that her own husband turns from her, believing the rumors.
Later that year, the scornful wife herself gives birth to twin girls. Terrified she will be judged by the same slander she had heaped on the first mother, she plans to murder one of the children. But her "maid of very noble birth" convinces her this is unwise, and instead offers to take one far away, leaving her at a church where she might be found and raised properly. Overjoyed, the mother promises the maid a great reward for such service. They wrap the girl in a rich brocade that the husband had brought back from the Crusades, and the mother ties to it a fine ring that will speak to the baby's noble heritage.
The maid undergoes a long journey through the woods at night, until she hears the sounds of a nearby town. She explores it to find an "exceptionally wealthy and well-endowed abbey," where she prays to God the child might find a home. Immediately after her prayer, she notices a large ash tree nearby and she hides the child in its branches before heading back home to her mistress.
That night, the abbey's porter notices the cloth and thinks it must be stolen goods stashed away. Imagine his surprise when he finds an infant! He brings the child to his widowed daughter, and asks the girl to bathe and suckle her, an order the daughter willingly accepts. Meanwhile, the porter tells the story to the abbess, who offers to raise the child as her own niece. Because of where she was found, they decide to name the girl "Le Fresne," which means 'the ash tree.' She is raised well and becomes such a lovely and well-spoken girl that "no one who had seen her would have failed to love and admire her greatly."
There is a great lord named Gurun who rules the land of Dol. He hears about this gracious girl, and makes a trip to the abbey on a pretext to meet her. He immediately decides he wants her, but fears alerting the abbess to his intentions. In order to secure visiting rights, he gives great sums of wealth to the abbey, which gives him "lord's rights." Through his many visits, the girl falls in love with him and he convinces her to become his lover. When his passion grows great enough, he asks her to run away with him. Her reticence is assuaged when he convinces her that becoming pregnant under the abbess's care would bring shame to her. So the girl, who has been told of how she was found, takes her tokens from her unknown parents and leaves to live with Gurun, where he and all his knights "love and honor her for her nobility."
However, Gurun's vassals are concerned about his lack of an heir, and demand he take a wife of noble line. When he finally agrees, they tell him about a man who lives nearby with a noble daughter known as La Codre, which translates to 'hazel tree.' They convince him that the names will speak to futures: "on the hazel there are nuts to be enjoyed, but the ash never bears fruit." The king agrees to marry La Codre, and when Le Fresne finds out, she does not show displeasure but rather acquiesces to serve her lord. What only we know, thanks to Marie, is that these two girls are the twins who were separated at birth!
On the day of the wedding, the mother of the girls is still thinking wicked thoughts. Worried that this Le Fresne whom Gurun reputedly loves might rob affection from her La Codre, the mother makes plans to banish the girl or marry her off quickly so as to remove her from Gurun's house. But when, at the splendid wedding, Le Fresne shows such submission and grace in the way she serves the new bride, even the mother finds herself impressed and loving the girl. The mother wishes to herself that her family had not caused this girl heartbreak.
That night, the bed is being prepared for the consummation, and Le Fresne joins the chambermaids to teach them how Gurun likes the bed made. When she sees the ordinary material with which the bed is decorated, she objects and demands they use her noble brocade. When the mother and La Codre come to the bedroom, the mother sees and recognizes the brocade and is frightened. She finds out that it did indeed come from Le Fresne, and then has the girl brought to tell her story. When the girl tells the story and produces the ring, the mother admits the truth and embraces her once-lost daughter.
The father is called, and the mother confesses her sins, and is pardoned. The archbishop and Gurun hear the story afterwards, and the former promises to annul the marriage the next day. Gurun then marries his beloved Le Fresne, the family is reunited, La Codre later finds a good marriage, and a lay was composed to celebrate it, which Marie now recounts.
This lay is notable for its multitude of perspectives and for its strong message of selfless love as the most noble of all. But even for its happy ending, it does not shy away from depictions of the wickedness in human nature or from the irony that pervades our lives.
The lay is split into two parts. The first part tells how the mother, worried of being shamed by her own slander, has Le Fresne brought away, where the girl finds a good home. The second part tells of Gurun's pursuit through the happy ending. The first part exists in uncertainty – other than the happy status quo of the beginning, the first part seems to suggest potential harm for all involved, and features much hatred from the spiteful mother. While the second part is dramatic and its outcome uncertain, it is clear that Le Fresne has found a great serenity in her submissive and selfless love and in this way do we never feel she will reach a tragic end. The maid (who brings the girl to the abbey) has to travel through the woods in the dark until she finds the abbey in the light of the morning, and perhaps this is a good symbol to explain the story's progression. Once all is set at the end of part one, the light remains through the goodness of Le Fresne.
There is much selfish love in the story, not only from the spiteful mother but also from Gurun himself. While Marie praises him as "the best" lord, it is worth noting his selfish way of both acquiring Le Fresne and then getting her to leave with him. While it certainly would be seen as virtuous to donate great wealth to an abbey, Marie makes it clear that "his motive was other than remission for his sins." Likewise, his argument to get her to leave – that her pregnancy could shame the abbey – is belied by his own desires. He doesn't care about the feelings of the abbess, but uses them as a rhetorical tool.
But what keeps the story from the tragic end that usually strikes selfish lovers in Marie's lays is the divine selflessness of Le Fresne. It is telling that we almost never get Marie's perspective into her feelings. She is one who lives for others. Perhaps this comes from having had her life enabled by selflessness. The maid who undertakes a terrible journey to save her life, the young widow who shares her own breast milk for another's baby, and the abbess who raises her are all influences that help explain how Le Fresne is so lovely and selfless.
Of course, the most selfless act of all is that which ultimately saves Le Fresne and helps her reclaim her birthright. Had she given in to spite or hatred for her beloved's new bride, it would have not only been understandable but expected. Because of this, her refusal to show any hate impresses everyone, and when she manifests this selflessness by offering her one noble possession – the brocade – to celebrate Gurun's betrothal, she starts the chain of events that will result in her recognition and happiness. Her love of Gurun is not about her – it is about him – and for this she is rewarded. Similar to the lovers of "Guigemar," because she accepts that suffering is a part of life and loves nonetheless, she is able to avoid a tragic end.
Marie has great fun playing with the irony of the concept of 'nobility' in this lay. Nobility traditionally would have referred to high rank, with the expectation that good breeding and genes would also engender the virtues that could be called 'noble.' And yet this definition is thwarted on several occasions. For one, nobility does not presuppose virtue. The spiteful mother is certainly not a good person despite her high standing, and the knights who so callously ask Gurun to abandon the girl do not exhibit selfless nobility at all. On the other hand, Marie calls "noble" many things that explicitly are not of high rank. She speaks of the selfless maid as "of noble birth," speaks of Le Fresne as being loved for her nobility long before the revelation of her true identity is made, and lastly notes that she is seen as noble by all those who admire her selflessness. The irony, of course, is that Le Fresne is noble by birth, but it is not birth that makes her worthy of the title, but instead the selflessness she learned from her lower class upbringing.
The entire lay is full of irony, since intentions produce their opposites. The mother's initial intention to murder the child is echoed when she hates the girl from afar before the wedding, and yet these feeling are entirely upended when confronted with the girl. The very qualities of low standing that disgust the mother from afar are the ones that impress her later. It all introduces the question of what to do with Marie's treatment of the mother – why is this woman not only not punished by the author, but instead given a happy ending of her own? Why is she so easily forgiven, where the first mother, slandered unfairly, suffers? Perhaps Marie means to remind us that the world's forces are not in our control, and the best people are ironically harmed, and vice versa. It also could be that Marie wished to stress the importance of selfless love, to stress the Christian understanding that such a virtue can save even the worst of sinners.
The final use of irony is, of course, in the names of the girls. Where Le Fresne contains within her the seeds for a happy ending for everyone, her name suggests she is barren (since an ash tree produces no fruit). Meanwhile, had La Codre ended up the bride, happiness might have been lost, despite the 'hazel' implications of her name (since a hazel tree produces much fruit). In truth, it is the basic, 'ash tree' upbringing of Le Fresne that produced the selflessness that saves everyone.
Lastly, this lay makes significant use of a common theme in the lays; that of hearsay. The use of gossip as a plot device is the most obvious, but also the reputation of Le Fresne is very much responsible for her story. Gurun seeks her out based on hearsay, and the mother plots against her based on the same.