The marriage plot is a uniquely satisfying and enduring narrative. It’s a simple form: Two people meet, fall in love, and encounter (and overcome) a few obstacles before ultimately marrying. Meanwhile, their long, troubled trip to the altar provides the narrative thrust of the story. It was developed in 18th-century novels like Pamela and Clarissa, and it lives on today in romantic comedies and romance novels.

But our most beloved marriage plots came to be in the 19th century, in the works of Jane Austen and Charlotte Brontë. Their novels — especially Austen’s Pride and Prejudice and Brontë’s Jane Eyre — defined and codified the genre. When we talk about marriage plots, we’re almost always, on one level or another, talking about these two iconic books.

So it’s no surprise that two of this season's new releases are adaptations of these beloved stories: Curtis Sittenfeld’s Eligible, a modernization of Pride and Prejudice, and Lyndsay Faye’s Jane Steele, which reimagines Jane Eyre.

They’re both successful adaptations — smart about which elements of their source material don't require any change versus which could use a quick sprucing up, and effective at drawing out interesting tones from the source novels — but they use very, very different strategies.

Modernizing Pride and Prejudice, as Eligible does, is a simple proposition

In Eligible, Austen’s 20-year-old Lizzie Bennet becomes 38-year-old Liz Bennet, a feminist writer who's been aged up to make her mother’s hysteria over her singledom slightly more believable. Meanwhile, Austen’s gentleman Darcy becomes a brain surgeon from a moneyed background. Instead of engaging in charged ballroom banter, they have hate sex.

Much of the pleasure of reading Eligible is in recognizing how Sittenfeld has updated the archetypes of Austen’s era with those of our own: Of course Kitty and Lydia, Lizzie’s officer-obsessed little sisters, are into CrossFit now. Of course that cad Wickham is a Nathaniel P. type. Austen’s comedy of manners is still funny when it’s applied to our contemporary world — her social satire uses the same template as ours does, and Eligible illustrates that, like The Lizzie Bennet Diaries before it. All you really have to do is update the brand names and the pop culture references.

Even if you want to focus on the romance more than the satire, you don’t have to work too hard to transform Pride and Prejudice into a straightforward romantic comedy. Bridget Jones’s Diary and Bride and Prejudice proved as much. We love watching Lizzie and Darcy meet, despise each other, and fall in love, no matter what time period they live in. It’s a story that is always funny and sexy and romantic, as many times as we tell it and retell it. Pride and Prejudice gave us an enduring romantic comedy formula, and it’s easy to update it with only minimal tweaking here and there.

Updating Jane Eyre is tougher because it's both a marriage plot and a gothic romance

You can’t do the same thing with Jane Eyre. Brontë wasn’t writing anything like a romantic comedy or a comedy of manners — she was writing a gothic romance that was also an aspirational marriage plot. And by gothic, I don’t mean something that would appeal to a Hot Topic–obsessed teen. I mean gothic as in the literary form that developed in the 18th century out of the romantic tradition, all sublimated rage and sexuality hidden in secluded country houses where men with tragic dark pasts stood broodingly on the ramparts.

Today, we love a good gothic romance — but we don’t usually love to see it paired with a marriage plot. We want the gothic love story to be tortured and tragic and doomed, and we’d rather the gothic hero be punished for his sins, not rewarded with marriage to the heroine. So we like Phantom of the Opera, as long as Christine ends up with Raul, not the Phantom. Flowers in the Attic is a trashy fave, but no one wants the Dollanganger siblings to get married. In Crimson Peak, the swoony, Rochester-quoting hero gets — spoiler alert — a knife to the face.

In a contemporary gothic romance, you understand the attraction, but the narrative must condemn and thwart it.

Jane Eyre never condemns the love story between Jane and Rochester, madwoman in the attic be damned. It never asks the reader to condemn the story, either. That’s just not how marriage plots work. Jane Eyre does not function if the book does not believe wholeheartedly in the rightness of Jane and Rochester’s marriage.

So when you try to turn Jane Eyre into a contemporary romance, you have to fight against either the gothic elements or the marriage plot. The results are uncomfortable. You end up with books like Jane, a YA novel that recasts Rochester as a 40-year-old rock star and Jane as his 19-year-old nanny. Or you end up with a web series like The Autobiography of Jane Eyre, where Jane is a nurse turned private tutor and Rochester a wealthy businessman. These adaptations hit the romantic element hard — but they they have no idea how to reconcile the romance with the gothic, and so the romance fails.

In a straightforward 21st-century romantic drama, it’s creepy for a wealthy, middle-aged man with a child to pursue his teenage employee. And it’s straight-up disturbing that he has his secret crazy wife locked in the attic in an era of humane mental hospitals and no-fault divorces. We don’t want that guy to have a happy ending. We want to see him punished.

That’s why the best modernization of Jane Eyre that I know of is the 2009 film An Education, which knows that if you're identifying your 20th-century schoolgirl heroine’s love interest as a "Mr. Rochester figure," you are identifying him as a villain.

Jane Steele adapts Jane Eyre into a thriller

Jane Steele is successful because it is neither a modernization nor a romantic comedy. Instead, it reimagines Jane Eyre as a blood-soaked thriller.

Title character Jane Steele is not, to be clear, Jane Eyre. Like Jane Eyre, she is a penniless Victorian orphan, and Jane Eyre is her favorite book. And like Jane Eyre, Jane Steele is sent off to a charity school by her wicked aunt, and eventually becomes a governess in a mysterious country house owned by a man who harbors dark secrets — with whom she will, inevitably, fall in love.

The structure of Jane Steele’s story echoes Jane Eyre’s, but when Jane Steele, like Jane Eyre, is attacked as a child by her wealthy and wicked cousin, she kills him. When, like Jane Eyre, she is faced with mistreatment and starvation at the hands of her sadistic charity schoolmaster, she kills him. And while Jane Eyre ends with the iconic line, "Reader, I married him," Jane Steele begins with "Reader, I murdered him."

What is subtext in Jane Eyre becomes text in Jane Steele

The pleasure of this adaptation does not come from watching familiar satirical tropes pick up present-day brand names, as is the case with Eligible. Rather, it comes from watching what was subliminal for Jane Eyre become explicit text for Jane Steele. Have you ever thought there was maybe something a little pervy about Mr. Brocklehurst’s obsession with "mortifying the flesh" of all the impoverished little girls entrusted to his care? Here’s his Jane Steele counterpart with a collection of sadomasochistic pornography. Did you think Jane’s love for her angelic schoolgirl friend might have romantic undertones? Here are their Jane Steele analogues kissing.

Most of all, Jane Eyre's pent-up rage and bitterness finds its outlet in Jane Steele’s cold-blooded murderousness. You always knew Jane Eyre wanted to stab Mr. Brocklehurst with a letter opener. Now you can watch her do it.

As a serial killer, Jane herself is as much a brooding Gothic hero as her love interest Mr. Thornfield, if not more so, and the book often sees her stepping into the Mr. Rochester role. One of her earliest encounters with Thornfield comes when, like Rochester in Jane Eyre, Jane Steele falls off her horse, injures her leg, and sits cursing in the lane. And in an echo of the scene where Rochester asks Jane Eyre if she thinks he’s handsome, Jane Steele approaches Thornfield and whispers, "Do you think me beautiful?"

The women’s gothic genre depends on constrained female emotions: All of the rage and fear and lust that women are socially forbidden from expressing come out in code. By making explicit what is coded in Jane Eyre, Jane Steele levels the emotional playing field and so solves the problem of the contemporary gothic romance: Jane Steele and Thornfield are equals. They are as bad and as good as each other, and so we are once again given permission to root for them to marry.

The difference between Pride and Prejudice and Jane Eyre is enormous

Pride and Prejudice and Jane Eyre are lumped together so often that we sometimes think of them as interchangeable, or as only the simplest possible variations on a theme: Austen’s novel is the cool, composed, witty one, and Brontë’s is the passionate one, but they’re both love stories and marriage plots, so how different can they really be?

But in 2016, what we want from an adaptation of Jane Eyre is entirely different from what we want from a Pride and Prejudice adaptation.

What we want from an updated Jane Eyre is not to bring Jane and Rochester into a contemporary world. They make no sense to us here. Instead, we want to give them contemporary psychologies, so that we can have the satisfaction of watching them act out their desires with impunity.

We don’t need to give Lizzie and Darcy contemporary psychologies. They’re already there: They think the way we think. We want to bring them into a contemporary world so that we can have the satisfaction of seeing how little things have changed since Austen’s day, of how close our two time periods really are.

Go ahead and read Eligible and Jane Steele if you like marriage plots. They’re good adaptations — smart and funny and evocative. But they are as different from one another as their two sources are.