I just typed this into a work email:
"Anyway here's my prediction for HBO's endgame. Avoid this if you are unfamiliar with the Tower of Joy:
The Mother of Dragons loads her Blood Riders, the Unsullied, and the Seconds sons onto the Masters' ships, as well as those of Yara's loyalists in the Iron Fleet. They head across the Narrow Sea under heavy air support from the Dragons of Mass Destruction.
Daenerys is still unaware of what's happening in the North, so she'd likely make straight for the Iron Throne (her ancestors took King's Landing with a mere TWO dragons). BUT HBO has to stall for half a season so she COULD go to help Yara win back the Iron Islands first. HOWEVER she'd be better off sailing through Old Valyria to take Dragonstone (since it's pretty much empty now).
Meanwhile in the North, Sansa will be busy drawing the strayed houses back to the Stark banner. Littlefinger will press Winterfell's alliance with the Eyrie now that he's betrayed the Crown by rising against the Boltons. The Eyrie's interests lie closer to Riverrun but the Knights of the Vale are pretty Olde School so if they see proof of White Walkers they might be inclined to maintain a garrison in the North.
By this point, Night's King will be at The Wall. He might decide to retake the Nightfort but more likely he'll march straight for Castle Black, and he'll probably be carrying the Horn of Winter (it was used to defeat him when he originally rose up). He'll use the horn to destroy the Wall.
The destruction of the Wall is likely to get all of Westeros's attention, but now that King Tommen is in the pocket of the High Septon he might still ignore it. Jamie Lannister won't though, so he'll take the army currently garrisoned at Riverrun straight up the Neck to Winterfell, just as he did with Robert Baratheon as our story began. However, this won't happen if Daenerys is attacking King's Landing and endangering Cersei. For the sake of the story, Cersei might decide to abandon King's Landing and make for Riverrun with The Mountain.
Now, this shit is called A Song of Ice and Fire for a reason, so it literally cannot end any other way besides Dragons vs Zombies. Sam is one of the only people in Westeros who will understand the advantage dragons have over Night's King, so he'll do everything he can to get that knowledge to the Mother of Dragons. Danaerys won't want to sit on the throne of a kingdom of ice wraiths so she's gonna have to burn those fools, likely at the most desperate/narratively exciting moment for Jon's forces.
Speaking of thrones, Jon Snow is the trueborn son of Rhaegar Targaryen and Lyanna Stark, so he actually has the clearest claim to the Iron Throne (son of eldest brother beating out youngest sister) and possibly even the best claim to Winterfell. So Danaerys is Jon's aunt. But she's also a Targaryen so it's totally NBD if they have sex and then rule the Seven kingdoms as Westeros's Hottest Couple.
-Arya will kill some people. She only has five names remaining on her list. Of those, Cersei, Walder Frey, and The Mountain are most likely. But it would be sweet if The Hound got to slay The Mountain.
-I have no idea where the Three Eyed Crow story is going but Bran will probably confront Night's King eventually. Maybe he'll Warg a Dragon. After all, the Last Greenseer did say he'd teach him to fly.
-Sam and Gilley live happily ever after. Or Sam dies horribly.
-Grey Worm dies heroically. In a shocking plot twist, Missandei breaks the 4th wall and becomes my girlfriend. Well played, HBO.
-X-factors: Highgarden, Dorne."