Why PLL: Original Sin's Kelly might actually be Karen (2023)

Pretty Little Liars: Original Sin spoilers ahead.

In the world of Pretty Little Liars, you should always know better than to trust a sneaky set of twins. This rule continues on through to its latest spin-off series, Pretty Little Liars: Original Sin.

But, just as creator Roberto Aguirre-Sacasa promised, this slasher-loving tale of a girl gang targeted by a mystery assailant is proving a little more bloodthirsty than normal – so much so, that one of the reigning bitch twins of Millwood's high school was offed by the end of the second episode in a killer twist to the already bloodythirsty Carrie prom homage.

Celebrating her new title as Spirit Week queen at the dance, a pregnant Imogen Adams (Bailee Madison) is left shellshocked and horrified as she witnesses frenemy Karen (Mallory Bechtel) fight with someone in the rafters of the school gymnasium before being pushed to her death.

Karen was never up there for good reason. In fact, under the guidance of her twin sister Kelly, she was ready to coat her former friend in red paint a la Carrie, only someone was already up there to meet her. This Leatherface-inspired mystery person is proving to be quite the menace to our gang of new Liars, and Karen was the first victim of this new 'A'.

Only, from the moment she plummeted to her death, viewers have been wondering... was it actually Karen up there, or was it Kelly?

The girls (played by the same actress) have an age-old habit of pretending to be each other. Heck, earlier on in the same episode Kelly was seen dressing up like her sister to talk to Principal Clanton, confessing to the number of horrific acts that saw all the leading ladies wind up in detention.

The pair are eerily alike in almost every way – the perfect identical twins (like we said, same actress) who would do whatever they can in order to get a foot up in high school and the town.

Karen became bitter when Faran won the role of Black Swan in the school ballet, arguing essentially it was because Faran was Black – she's that kind of girl. Similarly, the only reason she shunned former bestie Imogen is because she believed her boyfriend over her when they were caught kissing... a moment of drunk madness that Kelly actually saw, before relaying to her fuming sister.

Speaking about her dual roles, Mallory has told several outlets that there are small but noticeable ways she differentiated the two.

"It really helps that Karen was always showing more skin – you just carry yourself a little differently because of that. Karen was always in a heel, and Kelly always wore flat shoes, so she hunched a little more,” Bechtel told W Magazine.

"Karen furrows her brow a little more; Kelly keeps it up. Karen has her mouth open when she’s listening; Kelly keeps her mouth closed. Even my eye makeup is ever so slightly different."

"The simplified version of that for me is I think Karen is motivated by a need to just be the best at everything," she later elaborated to Teen Vogue.

"Kelly is the peacekeeper of the family. And if Karen is happy, her dad's happy. And so Kelly is going to do anything it takes to keep Karen happy. That's the easy way of doing it."

But it seems despite their obviously unique bond, Kelly has grown quite a resentment for Karen. In their home life, it becomes obvious very quickly that their father idolises Karen, to the point that he completely overlooks his second daughter. Their mother is also pretty removed from the whole situation, especially after Karen's death.

So Kelly's behaviour following her sister's very public demise has been stoic to say the least – in fact it's downright odd. Suddenly she's becoming more interested in ballet, she's making out with her dead sister's boyfriend at house parties, she's moving her things into Karen's locker... by all outside perspectives, she's becoming more and more Karen.

On the night of the Spirit dance, Imogen went to speak to Karen, only to be told it was actually Kelly – even scolded for confusing the twins. But then, so does Karen and Kelly's mother. We know she's got her own mental-health problems, but surely she'd know the difference between her daughters?

And if Karen has decided to take on the role of her sister, why? By accounts within the family, she was the favourite. Why would this popularity queen settle for the second role? Is it out of guilt for letting her sister die for her? Or maybe a morbid curiosity about how other people would react to her death, with the switch allowing her to watch it in real time?

Faran is so sure the twins have switched that she even confronts her about it at the Halloween party. (In frankly the most savage way – you might be wrong, girl, and if you are you'll have a hell of a lot of apologising to do because the way you spoke to Kelly/Karen was ridiculously harsh.)

But Kelly stands her ground, insisting she's Kelly before branding Faran a psycho and storming off. Kelly or Karen, we don't entirely blame her – Faran's lack of explanation sounded tantamount to a death threat and we would have been out of there.

However, Faran wasn't without her points. After razorblades were shoved in her shoes, Karen had scars on her feet – the same scars Kelly seemed to have on hers. Her fight for the same boy and sudden quest for popularity seemed unbecoming of Kelly, but very on brand for Karen. She had even picked up her sister's sayings and dismissals, as well as her abrupt behaviour.

We're surely going to find out the truth sooner rather than later – it certainly seems like a possible theory right now. It's just the big old "why?" that is a little cloudy.

A twist this obvious almost seems too obvious, for a show that likes to subvert expectations. But then... is that what they want us to think?

At the halfway point, the Kelly/Karen identity is officially as big a mystery as 'A'... and we can't wait to see how this plays out.

Pretty Little Liars: Original Sin continues weekly on HBO Max in the US, with a UK release yet to be confirmed.