Spoiler Alert

House of the Dragon‘s fifth episode started with Otto Hightower telling his daughter, Queen Alicent, her husband won’t live much longer. It then ended with Grand Maester Mellos giving the ailing King Viserys subpar care. Those two bookends, combined with some curious moments earlier in the season, make it impossible not to suspect a sinister scheme might be afoot against House Targaryen. And if there is, that could mean the Grand Maester Conspiracy, a major A Song of Ice and Fire theory, is absolutely true.

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The Grand Maester Conspiracy’s name comes from readers of George R.R. Martin’s novels. But the longstanding theory—which says maesters of the Citadel both spy on the families of Westeros for their own benefit and secretly undermine all forms of magic—comes from Martin’s characters.

One of them is Lady Barbrey Dustin of Barrowtown in the north. In A Dance With Dragons she questions maesters’ loyalty to their assigned houses. Maesters are meant to serve only the lords and ladies of the particular castles and keeps they’re sent to. But Lady Barbrey suspects those learnéd men share sensitive information among themselves. And they’d have a lot to share. They’re privy to every family’s greatest secrets. They’re als keepers of the Realm’s messenger ravens. That’s why she calls those figures clad in robes and chains “grey rats.”

(A term that obviously stands out when discussing House of the Dragon, which keeps showing rats in the Red Keep.)

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She’s not the only one who thinks maesters are more cunning and diabolical than they appear. But the opinion of Marwyn the Mage carries even more weight than Lady Barbrey because he is the archmaester of magic and the occult at the Citadel.

Marwyn the Mage is a notorious member of the male-only institution. He’s one of the few maesters to forge a link (made of Valyrian steel) for mastering the study of magic. He’s also rumored to associate with strange figures and engage in bizarre activites. And he spent years abroad studying with practitioners of sorcery. Because unlike other maesters, men of science and knowledge whom Marwyn calls “grey sheep,” he embraces the very things they shun. That includes dragons.

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Game of Thrones viewer knows at some point between House of the Dragon and Daenerys Targaryen’s rise to power dragons go extinct. They will not return until the Khaleesi emerges from the ashes with her three “children.” Marwyn, eager to meet with Daenerys in the books, believes the demise of dragons was no accident. Nor was it a natural phenomenon. He believes maesters conspired to secretly kill off every dragon, animals connected to magic.

Dragons are the antithesis of everything maesters believe in. They’re intelligent creatures capable of independent thought that only a handful of people can even ride. Dragons very existence also undermines knowledge, science, and control itself, the very sources of maesters strength and beliefs. For everything dragons give to House Targaryen they take from maesters.

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But even if maesters don’t fear the magic of dragons, they might very well fear the destruction they bring. Dragons are “fire made flesh,” and for thousands of years they’ve killed countless people over two continents. Dragons might be majestic, but they truly do bring fire and blood wherever they go. They’re also destined to soon fight a brutal civil war of succession, a costly event maesters will witness up close.

If Marwyn and Lady Barbrey are right about the “grey rats,” the Grand Maester Conspiracy might have once been even bigger than they thought. Because House of the Dragon has hinted that maesters are conspiring against House Targaryen with a powerful ally—the Hightowers.

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House Hightower is one of the most noble ancient families in all the Realm. And their seat of power, a famous lighthouse castle, resides in Oldtown, one of the oldest and most powerful cities in all of Westeros. It’s also home to the maesters’ Citadel, which House Hightower has long protected. No family has a more meaningful and important connection with the maesters’ than Queen Alicent’s family.

Now Ser Otto Hightower, the former Hand of the King and grandfather to a potential Targaryen king, is positive Viserys won’t live much longer. Is that because Otto has seen Viserys naturally growing weaker? Or because he knows someone is making His Grace ill? The King certainly is not getting the best care from his own Grand Maester, a man who might very well want to see the blood of House Hightower on the Iron throne. And Game of Thrones showed us Grand Maester Pycelle was not loyal to King Robert Baratheon. Sometimes maesters serve themselves.

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From not knowing how to treat open sores, to the unexplained death of the king’s newborn son, to the many untreated wounds of Viserys, the current Grand Maester, Mellos is doing a terrible job. Even Orwyle, the new maester introduced in episode five, agrees. He tried providing Viserys with other treatments that might actually help.

But he might be the only maester trying to serve House Targaryen. But that might not be enough to save Viserys, House Targaryen, dragons, or the Realm from the Grand Maester Conspiracy. Because we might soon learn one of A Song of Ice and Fire‘s most important theories was always true.

Mikey Walsh is a staff writer at Nerdist. You can follow him on Twitter at @burgermike. And also anywhere someone is ranking the Targaryen kings.