WARNING: Spoilers for all episodes of Game of Thrones up to season 8, episode 3.

Was the episode title for Game of Thrones' Battle of Winterfell episode, "The Long Night", a spoiler? Secrecy around the HBO fantasy series has reached a new level in the final season. For the past few years, no screeners have been made available to press, and now the network's not even announcing the names of new episodes until after they air.

This was assumed to be hiding spoilers, although the full reasoning wasn't initially clear. The Game of Thrones season 8 premiere was titled "Winterfell", a pretty expected name for an episode that's about the army of the living convening at the Stark castle. Season 8, episode 2 was a little more revealing: "A Knight of the Seven Kingdoms" references Brienne's knighting care of Jaime, and as the name of a Tales of Dunk and Egg short story, would have clued book readers into that possibility.

Related: Game Of Thrones: Everybody Who Died In The Battle Of Winterfell

But Game of Thrones season 8, episode 3's secret title may blow that out of the water. This was the Battle of Winterfell episode, the final stand against the Night King's army and one that went a little different than expected. At the end of the episode, when all hope seems lost as a bigger-than-ever horde of wights swarms the survivors and their leader moves to kill Bran Stark aka the Three-Eyed Raven, Arya leaps in and stabs the Night King with a valerian steel dagger, destroying all White Walkers and their zombie army. In a shock twist, Game of Thrones' big threat is killed halfway through the final season.

So what was this called? "The Long Night". Now, on the surface that's hardly a spoiler: it was, indeed, a very long night for all involved. But to fans of George R.R. Martin's A Song of Ice & Fire books on which Game of Thrones is based, it's a different story.

Arya and Night King fight in Game of Thrones

The Long Night is one of the longest recorded winters in Westeros (and beyond) during which time The Others (how White Walkers are described in the books) first attacked. They were eventually driven back by a mysterious figure known as the "last hero" or Azor Ahai, depending on your culture, which led to the building of the Wall. Melisandre insisted another Long Night would come again to Stannis in season 5, which is what finally came in season 8, episode 3.

Had it been known that the latest Game of Thrones episode was titled "The Long Night", then fans - especially those up on book lore - would have been able to speculate more directly than was otherwise possible that this wasn't just a battle against the White Walkers, but the true final stand; that it must end with the Night King's defeat in one form or another. This surely justifies keeping the episode titles a secret.

Related: Game of Thrones: What Happened To Jon's Dragon

Of course, there could be even more spoiler titles to come. The death of the Night King means that Cersei is now the big final threat of Game of Thrones and, without millennia of history and prophecy (valonqar aside), there's not much to suggest what will happen. The trailer for episode 4 is light on plot details, and titles would surely reveal more than HBO would like.

As for the Long Night, that is expected to be explored as part of the Game of Thrones prequel show premiering in 2020. This will surely explore more of the White Walkers' origins and goals that were ignored by the parent series.

Next: Game of Thrones Season 8 is (Literally) Too Dark

Game of Thrones continues Sundays at 9pm on HBO.