Cast your mind way back to season 2 of Game of Thrones. In the finale episode, Daenerys Targaryen enters the House of the Undying, where she has a vision of Khal Drogo and hears some cryptic words from Pyat Pree. It's a fantastic scene.
The chapter it's taken from, though, 48 in A Clash of Kings, is more insane. In the book, Daenerys sees a vision of a man who appears to be her brother, Rhaegar, with a woman and a baby. Rhaegar tells the woman "He is the Prince that was Promised, and his is the song of ice and fire."
"The Dragon has three heads..."
Rhaegar then states that "There must be one more... the dragon has three heads". He then proceeds to play a harp, as is customary after making bleak prophecies about heirs and dragons. The three heads comment, on the surface, is merely a reference to the banner of the House Targaryen...
But it can also be read as a reference to Daenerys' ultimate reclaiming of Westeros. If we believe that two riders will conquer the Seven Kingdoms riding dragonback alongside Dany, Rhaegar's prophecy begins to look somewhat accurate.
Personally, I'm a big subscriber to the theory that Rhaegar fathered Jon Snow with Lyanna Stark. It makes perfect sense, particularly if you take the view that Nedd Stark, widely considered a man of great honor, is unlikely to have broken his vows to Catelyn whilst at war in the South.
The blue flower growing out of the ice in Dany's vision at the House of the Undying could be read as a confirmation, blue winter roses having often been referenced as being Lyanna Stark's favourite flower. With that in mind, we have two of our three "heads" lined up: Daenerys Stormborn, and her nephew Jon Snow.
Speculation about the identity of the third head is wilder, but the most frequent name that pops up is Tyrion Lannister. Sure, it could be Tyrion, if you believe he's the bastard son of the Mad King. Two bastard son reveals, though? That feels like the kind of repetition that George R. R. Martin would try to avoid.
My theory is this: the third head is Aegon Targaryen. As in, the one who died. There are too many circumstances surrounding the infant's death that imply he plays a far more important role in the saga than we realised: for one thing, Kevan Lannister recalls that nobody had dared to identify the dead child at the time...
And why would Martin introduce the young Aegon in the first place? His death is effectively without consequence, a footnote in the history of the House Targaryen... unless he didn't die at all. Aegon's is "the song of ice and fire", which happens to be the title of the entire series. That doesn't strike me as coincidence.
Above all, Daenerys riding on the back of her dragons with Jon Snow and Aegon at her side and the intent to conquer Westeros would be the ultimate symmetry to the original conquest of Westeros by the House Targaryen, when Aegon rode in with his sisters Rhaenys and Visenya at his side. It's a mirror image too perfect to resist.
Of course, it's possible that this will never play out in the TV series, particularly with the need to divert from the source material now that Martin's rate of productivity has slowed from a fast canter to a relaxed trot. There's also the fact that the vision of Rhaegar never made it to screen in the House of the Undying sequence.
But I have hope, because Daenerys, Aegon and Jon Snow returning Westeros to Targaryen rule would be quite simply the most insanely epic thing in the history of television and fiction. Make it happen, guys.
Game of Thrones season 6 begins, finally, April 24 on HBO.