Game of Thrones season 6 is going to have some big, big, very big spoilers in it. I mean, we knew that already—the new season is going to be firmly in Winds of Winter territory, and that book hasn’t even come out yet. We’re not sure when it will, and it looks like 2016 is highly likely, but the new book and the new show are going to have some major revelations. One of them we already know, and it’s definitely going to be in Game of Thrones season 6: R+L=J.

How We Know Game Of Thrones Season 6 Will Reveal R+L=J

Spoilers henceforth for all Game of Thrones books. First off, if you don’t know what R+L=J means, here’s the short version (the Wiki has the long version): According to the theory, which fans have held for years and is strongly supported and hinted at in the books, Jon Snow’s true parentage does not involve Ned Stark. Instead, he is the son of Ned’s sister Lyanna Stark and Rhaegar Targaryen, who abducted, absconded, or eloped with her in an action that brought about Robert’s Rebellion and the downfall of three centuries of Targaryen rule.

Jon Snow was born toward the end of the war and Lyanna died in childbirth, an event that, according to the theory, took place at the Tower of Joy on the Dornish Marches. The tower was protected by three members of the Kingsguard when Eddard Stark and his companions arrived. Only Eddard and his friend Howland Reed survived. Eddard spoke to Lyanna, who died in blood in his arms.

And this scene, the Tower of Joy, is going to appear in Game of Thrones season 6. Winter Is Coming has a good rundown of the details, involving the cast list and some of the locations where the show is filming—notably Spain’s Castillo de Zafra. It’s not a sure thing yet, but the tower looks a hell of a lot like someplace on the Dornish marches, and Jon Snow’s secrets need to be revealed sooner or later—even if Jon Snow is dead and stays that way, which he is, and won’t.

The show has broken its no-flashback rule once already, so the seal seems to be broken. And Jon’s true parentage is so important that it deserves more than a mere conversation. It will be shown. Whether it will come from Bran’s new greenseer memory or from the mouth of Howland Reed, the one other survivor of the Tower of Joy, is yet unknown. In the books, I’d wager money it’ll be from Howland, but the show hasn’t introduced him except as Jojen and Meera’s offscreen father.

It’s going to be a big season. And revealing Jon Snow’s true parentage, a secret since the very first book, is just going to be one major step in closing the loop on plotlines. The world of Game of Thrones has perpetually gotten bigger, but it’s going to start to narrow—to Westeros, to the North, to the war with the Others. And Jon Snow, who is a son of a Targaryen (but probably not a Targaryen), is going to play an integral role. It’ll all start at the Tower of Joy.