Marie introduces this lay as a famous story about "two young people…who both met their end because of love," thus giving away her ending.
Though immortalized by the Bretons in a lay, Marie's story takes place in Normandy, near a "marvelously high mountain." Nearby, a king once built a great city called Pitre. That king has a beautiful daughter to whom he has been overly attached ever since the death of her mother. When rumblings amongst his court about the inappropriateness of his protectiveness reach him, he devises a plan to offer his daughter for marriage while simultaneously making such a union impossible: whoever would marry her must carry her up the great mountain in his arms, without stopping to rest. Men far and wide attempt the feat, but while some make it halfway up the mountain, none can succeed.
One young man in the realm, an honorable son of a count, falls in love with the girl while visiting her father's court. The young man worked hard "to be esteemed above all others," and the girl, impressed by how well the king takes to the youth, falls for him as well. For a while, they continue their affair in secret, the youth realizing that haste could ruin their union. But their secrecy ultimately upsets him, and he proposes they elope. The girl refuses – such a move would upset her father too greatly – and she also notes the boy's lack of strength that would prevent him from beating the father's test. However, she does propose a different plan. In Salerno, the girl has a rich aunt well versed in potions, and should the boy bring a letter from the girl, the aunt could make him a potion to increase his strength so he could win the test. He could then propose to her and easily carry her up the mountain.
Overjoyed, the boy undertakes the trip and is given a potion to revive his strength by the aunt. He returns quickly to the king and asks for the girl's hand. Though the king is saddened that such a weak boy, who will surely fail where stronger men have failed, would ask for such punishment, it is granted. The king makes preparations, inviting vassals from throughout his land to come witness the event. Meanwhile, the girl begins to starve herself so as to drop weight and lighten his burden.
When the day comes, the meadow is full of people as the boy begins his trek, carrying the girl who wears as little clothing as possible. She carries the potion so as to pour it into his mouth, but Marie tells us, "I fear it will be of little avail to him, because he knew no moderation." He makes it halfway easily from adrenaline, at which point the girl reminds him to take the potion. However, he tells her he feels strong and does not want to be distracted by the shouts he would hear from the crowd below were he to slow down.
He makes it two-thirds of the way, and she continues to beg him to take the potion, requests he continues to deny. He makes it to the top but at such cost that he falls down, immediately dead. Distraught, the girl attempts to revive him, to no avail. In a fit, she throws the potion over the landscape, and the land at that part of the mountain continues to grow "many good plants" because of it.
The girl lies down next to him, kissing his dead face, and she too dies of sadness. When the king finds them both dead, he collapses into a swoon. They are left there three days, after which coffins are brought and the dead lovers are buried on the mountain.
Because of this tragic event, the mountain is called "The Mountain of the Two Lovers."
This lay carries an impressive amount of depth for its short length. Titled "The Two Lovers" (as translated from French), it is straight to the point and yet carries Marie's typically complicated morality.
As usual, there is a general condemnation of selfish love, love that does not consider the other person. The king is extremely emblematic of such a perverse love. While no explicit claim is made of incest, there are many classical models that would take that extra step. Regardless of any sexual innuendo, the king's protectiveness of the girl is entirely self-serving. As Marie tells it, he keeps her close not because of her, but because he is saddened by the death of his wife. She is not even a person to be loved, but rather a symbol of something lost, and because of this, the circumstances that enable the tragedy are established.
However, the worse crime is how the king's selfishness has ruined the girl. She is unable to see things except in terms of her domineering father. For instance, while Marie does not give us cause to doubt her love for the young boy, Marie does note that the girl falls for him partly because she sees how highly her father regards him. She is unable to see him except in terms of the father. Similarly, while she is entirely willing to engage trickery and strategy to marry her love – to the point of starving herself! – she will not go the extra step towards eloping with him. It is not a question of honor or propriety that bothers her, but only the pain it might cause her father. His selfishness has perverted her own ability to love.
The girl's decision to starve herself is also quite interesting. There is an implication that, because the father considers her not a person but only a symbol of his lost love, thus does she consider herself only a body. To an extent, she is objectifying herself in the otherwise noble move, seeing herself as an object to be manipulated.
Marie's lay does not ultimately blame the tragedy on selfish love, however, but rather on another of her favorite themes: moderation. As in some of the other lays, this story uses significant magical items and forces. Love is again treated as uncontrollable force – it strikes the boy without his intervention. And the potion is of course a classically influenced item, common still in folk and fairy tales. However, as usual, it is not magic which pushes the plot but rather the way that characters respond to the magic. And in this story, the ultimate end is caused by the boy's refusal to display moderation. He will not listen to her entreaties to take the potion, ostensibly because he will be embarrassed by the crowds down below. He wants to win completely, even though he'd already taken a journey to get the potion. Marie gives us indication of this personality trait when she introduces him as a boy who wants "to be esteemed above all others." It is not something she outright condemns, but she does seem to lament such lack of moderation as an unfortunate quality in people, since it can lead to disaster. One could go so far as to argue that the boy's love of the girl was too influenced by his desire to outdo others, to have for himself the much-coveted girl, since that would be in line with the few details Marie gives.
Lastly, Marie's authorial intervention is particularly interesting in this lay. She gives the end of the lay from the very beginning, as though to make sure we are affected not by the dramatic tension of the story but by the moral she is exploring. Further, she intervenes in the middle to explicitly tell us that the boy will fail because he refuses to show moderation. The intention here, as always, is to entertain, but this lay seems to have been designed to be a bit more deliberate in meaning than many of the others, which revel in contradiction.