Warning: this article contains spoilers for The Queen’s Justice, the third episode of the seventh series of Game of Thrones.

A Lannister, as any Game of Thrones fan will tell you, always pays his/her debts. Which is useful if you ever decide to buy one of them lunch (make it Tyrion, yeah?), but bad news if you’ve ever killed one of their loved ones. Because they will pay you back, tenfold.

This becomes all too apparent in The Queen’s Justice, when Cersei (Lena Headey) decides to spend some quality time with her two Dornish prisoners, Ellaria and Tyene Sand. The very same women who, remember, killed her daughter, Myrcella, with a poisoned kiss.

It goes without saying that crossing Cersei in any way, shape or form will provoke her. Murdering her beloved daughter, however, takes things to an entirely new (read: twisted and horrifying) level.

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Cersei begins her psychological torture by chaining the mother and daughter to opposite walls and gagging them. She then gently kisses Tyene (Rosabell Laurenti Sellers) on the lips – and, yup, she soon reveals that her lips have been laced with the very same poison they used on Myrcella.

But Cersei's version is worse, because she forces Ellaria (Indira Varna) to watch her daughter die slowly across from her in her cell. She even promises Ellaria that they'll force-feed her and keep the lights on to make sure she doesn't miss a single moment of her beloved daughter’s demise.

A grim death? Of course. But it was by no means as significant as the death of everybody’s favourite badass, Olenna Tyrell (Diana Rigg) – a death that could have something to tell fans about Cersai’s own fate.

Olenna has, ever since she first appeared on the show, proven a worthy foe for the Lannisters – and has provided wise counsel to plenty of powerful women on the show, including Sansa Stark (Sophie Turner), Daenerys Targaryen (Emilia Clarke), and her granddaughter Margaery (Natalie Dormer).

So, when Jaime (Nikolaj Coster-Waldau) storms Highgarden and finds her alone in her chambers, it comes as no surprise that she’s grimly resigned to her fate. Nor is it a surprise that she has an epic final speech prepared. A speech which, we suspect, may hint at Cersei’s eventual fate.

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“I did unspeakable things to protect my family,” she tells a respectful Jaime. “I never lost a night’s sleep over them. They were necessary, and whatever I imagine necessary for the safety of House Tyrell, I did. But your sister has done things I was incapable of imagining. That was my prize mistake – a failure of imagination. She’s a monster, you do know that?”

Olenna goes on to accept Jaime’s offer of a poisoned chalice and a painless death, but not before she drops a few more truth bombs.

“I’d hate to die like your son,” she says, recalling Joffrey’s fate. “Clawing at my neck, foam and bile spilling from my mouth, eyes blood red, skin purple… it must have been horrible for you, as a King’s Guard, as a father.”

And then, finally reassuring Jaime that his brother Tyrion (Peter Dinklage) was not Joffrey’s murderer, Olenna adds: “It was horrible enough for me. A shocking scene – and not what I’d intended.”

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However it was Olenna’s comments about Cersei that really pricked up the ears of diehard fans.

“You love her, you really do love her,” she says to Jaime. “But she'll be the end of you. If she’s driven you this far, it’s gone beyond your control. She’s a disease and I regret my role in spreading it.

“You will, too.”

It’s an oddly portentous moment: Jaime may love Cersei – and, yes, he still lusts after her, too – but we’ve seen him grow more and more appalled over her behaviour as the series progresses.

Plus we have Maggy the Frog’s prophecy to think about, too.

As we learned in George R R Martin’s books, a young Cersei sought out fortune-teller Maggy and asked her to look into her future for her. And the future that Maggy saw for her was grim indeed: she revealed that Cersei’s husband, Robert, would become a father 20 times over by bedding a number of mistresses – a prediction which has since proven to have come true. Maggy went on to warn that Cersei would outlive all of her own children (again, true) – and that “another, younger and more beautiful” will come forth to cast her down.

But it’s the final part of the prophecy that’s truly interesting: Maggy reveals that Cersei will be murdered by the valonquar (which is High Valyrian for “little brother”).

“And when your tears have drowned you, the valonqar shall wrap his hands about your pale white throat and choke the life from you,” she told her.

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For years, Cersei assumed that Maggy had been referring to Tyrion – but what if she meant Jaime?

The pair of them may be twins, but we know that Jaime was born shortly after his sister, grasping her foot in his hand. And, sure, he may be her right-hand man now – but, in the books, we know that the two suffer a devastating blow to their relationship when Jaime learns that Cersei has been unfaithful to him. As this interaction has been left out of the show so far, it stands to reason that their love is balanced on a knife-edge: something is due to drive them apart in a very big way.

It is also worth remembering that Jaime killed Mad King Aerys because he wanted to save the common folk from being burned to a crisp. Cersei, similarly, has proven herself to be a less than benevolent ruler who does not have the people’s best interests at heart. After his prolonged exposure to Brienne (Gwendoline Christie)’s stubborn code of honour, could the Kingslayer be willing to sacrifice everything he holds dear to save the people of Westeros from his murderous sister?

Whatever happens, it’s safe to say that Jaime will be keen to seek out his brother, Tyrion, now that he knows his brother did not murder his son. And, with Tyrion working hard as Daenerys’ Hand, it seems also safe to assume that this won’t go down all too well with Cersei.

Images: HBO