@Lulee, great post! Thanks to all for the fun predictions. Here're mine...
Wild predictions:
Night King reanimates the dead in the crypts.
The little girl down there battles valiantly to save the living.
White Walkers win at Winterfell, but some survivors retreat.
Survivors defeat the Night King by tying together threads of magic, such as:
Dany sacrifices herself to save Drogon, gets reanimated by NK;
Jorah plunges that Tarley sword through her heart, destroying his former love;
Arya kills several White Walkers with her new weapon, enabling Bran to survive;
Jaime plunges his sword in into Cersei's heart, revealing his sword as Lightbringer while fulfilling prophecy;
To stave off the Long Night, Jon realizes he is the Prince That Was Promised;
Jon replaces the Night King, reanimates the new dead, and takes them north to lead them away from the Seven Kingdoms;
Bran the Rebuilder renews the wall after Jon leads the New Dead beyond it.
Bronn still wants his castle. Jaime says he'll have it as soon as he defeats marauders from the Iron Islands.
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Watching via HBO Now on laptop.