Why HBO's Run is the thirstiest show on TV right now

I see your lush romanticism of Normal People, and I raise you the totally twisted sexual tension of Run.

It should come as no surprise, given its roots, that the desire that is fundamentally apart of Run has the power to leave you breathless. The HBO show (Sundays at 10:30 p.m.), which stars Merritt Wever and Domhnall Gleeson as former lovers who enact a plot to run away together, is from the mind of Vicky Jones. Jones is the long-time creative partner of television darling Phoebe Waller-Bridge, having directed the stage version of Fleabag and written for Killing Eve. Waller-Bridge is also an EP on Run. After Waller-Bridge managed to make the world thirst after a priest last summer, it’s not exactly shocking that Jones has been able to mine a similarly taboo, off-the-rails situation (pun so intended) to expose the mechanics of desire.

Wever plays Ruby, a married mother of two, who blows up her entire life seemingly just to feel something again. Gleeson is Billy, a snake oil salesman of a motivational speaker, who is just as desperate as Ruby to free himself from the prison of the life he feels he’s created (or maybe is using the entire experience as fodder for a book – it remains to be seen).

A large part of the tension and attraction comes from the ingenious casting. Gleeson and Wever have such electric chemistry they probably have the power of resuscitation. There’s a devil-may-care energy to both of them that turns the flippancy of their side-eye into eye-banging without even trying. Wever has a sensual, earthy energy, the type that has catapulted the likes of Lauren Bacall and Kathleen Turner to stardom, while Gleeson is all boyish smirks and unfettered playboy glee. Taking an impromptu cross-country train trip leads to the kind of mussed hair and bedroom eyes that feel almost intrusive to bear witness to.

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As Billy and Ruby, the actors walk a tightrope of barely suppressed desire and adrenaline-fueled dread. They’re both keeping secrets from each other, weighing the consequences of their choice to run out on their lives while simultaneously wanting to rip each other’s clothes off. These are two people who want each other so badly they have to relieve the sexual tension by themselves in a train lavatory. That is next level thirst. As actors, they know just how to play it, tortuously and sensuously, with Wever regularly licking at the side of her mouth and Gleeson placing his hands on Wever's face for maximum oomph factor.

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These two also know how to banter like they’ve been thrown into a Golden Age screwball comedy. Two people who know how to eviscerate each other with their words, while simultaneously turning each other on, has been hot since Shakespeare wrote Much Ado About Nothing. Besides their banter, they also engage in dirty talk, something which is rarely played for anything but laughs on television. Here, though, it’s deadly serious, the verbalization of their long-suppressed desire.

The always simmering yearning between Ruby and Billy aside, there are plenty of other factors that up the ante. Run is bursting with tropes that the romance genre has perfected. On an elemental level, it’s a second chance romance, an exploration of an oft-tantalizing “what if?” when it comes to the ones who got away.

The train and the hotel room Billy and Ruby share introduces another beloved trope: there’s only one bed. It’s hard to ignore crackling sexual tension when you’re shoved into a room with a bed that will barely hold two people. The absurd forced proximity of the train sleep-away car is played both for laughs and as a tinderbox for Billy and Ruby's explosive need for each other.

Then there’s the tried-and-true “danger bang.” Are your hero and heroine in mortal peril? Definitely make time for them to put that pent-up "my life might end" energy into some lusty bed sport. From a practical standpoint, it doesn’t make much sense, but from a fantastical one, the idea of channeling all that adrenaline into something so life-renewing is undeniably appealing. It's been used for decades to great effect in romantic suspense novels, and Jones channels it expertly into this darkly comedic thriller meets love story.

We should also not underestimate the power of setting the events of this series predominantly on a train. Alfred Hitchcock understood the inherent horniness of trains; he used them to infuse eroticism into everything from North by Northwest to Strangers on a Train. They are a full steam ahead phallic metaphor for heaven's sake.

Particularly today, when trains are no longer the dominant mode of cross-country travel in the U.S., there’s also something decidedly romantic about them. They allow characters to travel through space and time, locked away inside their own bubble. The outside world passes by, always visible but just out of reach, which creates a tension between the consequences of reality and the freedom of the train's otherworldly isolation. On a train, Billy and Ruby can get lost in each other, but one glance out the window reminds them of what they’re running away from.

Lastly, though, there’s something undeniably erotic about the taboos of Billy and Ruby’s relationship. Who hasn’t at some point day-dreamed about running away from it all and embarking on a wild love affair? Actually doing it is another story, but THEY GO THERE.

Billy’s got more secrets (and perhaps ulterior motives) than we can count, while Ruby is literally cheating on her spouse (who, to be fair, doesn't seem like the best of dudes). In each other, they can find the fulfillment they’re clearly hungering for and can’t find in their home lives. While Ruby has a complicated, unsatisfying relationship to her marriage and motherhood, Billy has sought adulation and monetary reward from audiences and found it wanting. They’re contemplating giving up carefully built lives for each other. That’s a level of attraction and devotion that defies reason, and it’s one most of us would never even contemplate acting on.

Run approaches a third-rail of sexual expression, one that often is reduced to humor (or when played seriously still infantilized with labels like "mommy porn"). Part of this arises from Ruby's role in the situation. She has sexual agency and appetite, pursuing Billy and repeatedly pushing him to have sex with her. Her desire matches, if not exceeds his own, and it's rare to see that level of unfettered want from a female character that's not meant to reflect deviancy or invite censure. Ruby is far from perfect, but she is refreshingly allowed to be a woman who wants sex. She shares that with Waller-Bridge's Fleabag, but in a way that feels less louche.

With each episode, Run becomes more suspense-thriller than train romp, but that only ratchets up the sexual tension, plunging Billy and Ruby further into a mess of their own making. Their desperation seemingly only heightens their want. There’s nothing noble or particularly aspirational about their choices. They’re just two messed up people, fumbling toward each other because they can't help themselves.

It's the ultimate fantasy smashing into the reality of foregrounding our most primitive desires above all else. We should look away, but we can't help but run toward them. With Billy and Ruby, it's all aboard for an id-fueled train ride of epic proportions.

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