Félix de Vandeness, a sickly, neurotic, but highly intelligent adolescent who rather reminds me of Proust's narrator, is at a ball in a provincial town when he lays eyes on the most beautiful woman he's ever seen. As one does, he can't stop himself from sexually assaulting her. Surprised and offended, she leaves, but he makes inquiries and tracks her down. What happens next is the subject of a long letter, the main body of the novel, which Félix is writing many years later to Nathalie, the woman who then is his mistress. He frequently begs her pardon and trusts that she won't be offended by all the things he's telling her about this tragic period in his life. He wants her to understand him, you see.
Félix discovers that the woman from the ball is the Countess de Montsauf. She's married, has two children, and doesn't get on well with her much older husband, a ruined aristocrat, who appears to be suffering from hypochondria, PTSD, anger management problems and incipient senility. But Félix, who's a crafty little thing, manages to inveigle himself into the Count's good graces. The one thing the Count likes to do is play backgammon; Félix is always ready for a game, even though the Count insists on playing for money that Félix can't afford and is a terrible loser. The Countess is grateful that this kid is distracting her husband and forgives him.
Pretty soon, Félix has established himself as a regular visitor. Every time he gets a chance, he repectfully tells the Countess about his undying love for her, laying on the poetry and Christian sentiment as thickly as possible. He spends hours every day looking for flowers so that he can present her with exotic bouquets. The Countess barely knows anyone else; no one wants to visit the house because her husband is so horrible. After a while, it's clear that she's begun to reciprocate Félix's feelings for her. But although she's more or less stopped sleeping with the Count, she won't sleep with Félix either. She's very serious about her Christian principles, and tells him he can only think of her as a mother. She is in fact just ten years older than him.
The Count sees what's going on without properly admitting it to himself. He becomes seriously ill and for weeks hovers between life and death. His wife and Félix nurse him back to health, trying their hardest not to think how extremely convenient it would be if he would just die. (Those damn Christian principles!) In his parenthetical asides to Nathalie, who's reading all this in his novel-length letter, Félix says it's the happiest period of his life. He can be with the Countess all the time while they're looking after their patient. She's often informally dressed, he can check her out as much he wants. Sometimes their hands touch.
The Count survives and Félix goes off to Paris. The Countess has pulled strings (her family is powerful and well-connected), and at twenty-three he gets an important job working directly for Louis XVIII, who's back on the throne after the fall of Napoleon. For a while, all goes well; Félix lives chastely at court and exchanges regular letters with his guardian angel. But alas, a depraved English aristocrat, Lady Dudley, decides she has to seduce the King's new favourite. Félix resists nobly (or so he tells Nathalie, at least), but Arabelle is too cunning. She gets him into her bed. Unlike the Countess, she's a sexy bitch who's up for anything. I was quite surprised at the things Balzac manages to tell us without using any rude words.
Félix has been dumb enough to believe he can keep it secret, but needless to say the Countess finds out. She's heartbroken; on top of everything else, she can't even admit she is (those Christian principles again). She stops eating, pines away in a couple of months, and dies after a touching reconciliation scene with Félix. She leaves a letter, to be read after her death, telling him that she has loved him passionately the whole time. When Félix gets back to Paris, he finds that Arabelle has broken off their relationship. He's said multiple times that he didn't want her anymore, but he's still seriously annoyed to be the one getting dumped. Just to put the cherry on the ice-cream, the Countess's daughter has figured out what's happened and says she never wants Félix in their house again.
Ah! concludes Félix at the end of his long letter to Nathalie, you can see why I look a bit sad at times. But darling, I know you'll understand me. Jesus Christ, I was thinking, it is a bit hard to remember that this was the early nineteenth century, people viewed relationships between men and women differently then, you need to evaluate these things in context, etc etc. Imagine my surprise when I turned the page and read Nathalie's reply. It could have been written yesterday: dripping with sarcasm and hurt feelings, she says she'll obviously never be able to compete with hot Arabelle or the saintly Countess; she's also less than impressed by the fact that he repayed this woman's many kindnesses by killing her. She tells Félix, though at greater length and in flowery French, to be careful not to let the door hit him on the way out.
Unfortunately, the edition I'm reading has no footnotes or introduction. But doing a little googling, I find that Le Lys dans la vallée was published in 1836, four years after Balzac began his liaison with Ewelina Hańska, who took a lively interest in all his writing. Furthermore, it appears clear that the character of the Countess is based on that of Laure de Berny, a woman 22 years older than Balzac, with whom he was very close. Is it possible that Mme Hańska wrote Nathalie's reply? If anyone knows more, please tell me!