Dragonglass is going to save the day. We've seen it kill White Walkers, which by itself is unspeakably awesome. We've known for some time that the people of the Seven Kingdoms will have to arm themselves with dragonglass weapons to stop the Night King and his army. In episode one of Season 7 of Game of Thrones, Jon Snow, the new King of the North, decrees that dragonglass must be mined for this very purpose. As it just so happens, Samwell Tarly has a revelation at the same time on the other side of the continent: They can mine Dragonstone for dragonglass.
Anyway, Sam is at the Citadel in Oldtown, from whence (because 'whence' feels appropriate in a Game of Thrones discussion) the maesters study the world. And he's just discovered a big book of everything we need to know about the series going forward, including the use of dragonglass as a cure for greyscale. Convenitently, Jorah Mormont is hangning out in the Citadel, seeking such a cure.
Odds on Sam Tarly curing Jorah Mormont? Seemingly amazing. According to the snippet of text we can see in the episode, dragonglass does it all. So, what are the implications of Sam's book, and what does it mean for the rest of this season (and, indeed, the series)? Let's find out.
Obviously, this list is dark and full of SPOLIERS.
Prediction: The Seven Kingdoms (or at least what's left of them) will band together in the end to stop the White Walkers. Happy ending, right?
Nope. This is Game of Thrones, remember? Everything is horrible and everyone dies. Valar morghulis. The conclusion of the series will depict the benevolent rule of the Dragon Queen, Daenerys Stormborn, from her seat on Dragonstone ruling southern Westeros, having ceded the North to her friend the King of the North, Jon Snow. But just as it ends, we will get a hint that Daenerys is starting to show signs of madness. And the cycle will repeat itself.