OOOO a spoiler thread - good
Ok, so, Jon Snow is going to be the third betrayal to Dany - In order to save the realm, he'll have to bargain with the Night King (how you say?) well, once Jon recognizes that the Night King is really Bran, stuck within the Night King when he travels into the past to attempt to stop the Night Kings creation by the Children of the Forest, and wargs into the first man (from season 6), Jon and the Night King will come to an agreement of sorts in order to stop the armies of the dead and keep more from rising up. (only killing the night king can stop the entire army from rising up - since you can burn them, you can kill them with dragon glass and valerian steel, but any normal man or woman who dies will still rise up to become a white walker so unless you kill everybody in the realm, the only way to stop it is to stop the Night King) so, in realizing that the Night King is Bran, Jon will come to the agreement of finding the children of the forest, or what remains of them, in order to release the Night King from this multiple thousand year old curse set upon himself for trying to stop the entire whitewalker fiasco, since, by this time Bran will have gone mad (hence partially the reason for the attacking!) and he will do anything to be released from this self given curse - believing the only way to do this is to destroy the realm and appease the Other (who is the god of winter basically) before the god of winter will release him. BUT Jon finds out that this god is locked away in Winterfells crypts, bound by the magic of the children, and a blood ritual on the first stark (Brandon the Builder, also Bran - but we'll get there in another post) binding it there, only able to break free when a stark is not at winterfell, which, in this case, the magic is weakened and can be broken by destroying the crypts and the dead starks who guard it (the dead starks buried there obviously count as a stark in winterfell - guarding the god of winter, the Other from escaping) When a living stark is not at winterfell, (if anyone has noticed) the spell begins to break slightly, already releasing winter far faster than ever before (winter began to descend upon the realm far faster once winterfell was without living starks after theon took it over and the remaining stark boys fled! This caused a ripple effect and a series of events that began to break the spells that bind the Other...THEN, when Ramsay burnt winterfell, the chains broke even more, as the gargoyles protecting the entrance of the crypts were destroyed and were part of the binding. This also caused winter to come EVEN quicker, which can be seen if one notices that the walkers and the cold winter they come in on begin to occur more rapidly and more often in G.O.T. scenes. SO, Jon bargains to find the remaining children of the forest to end the curse they gave to the first man for him to become the Night King by convincing the Night King that he can do this by using the same ritual performed by the children as well as the ritual that binds the Other (binding the curse essentially and allowing Bran to warg out, and/or, the Night King to turn back into a normal man. BUT, Dany does not agree, and so they become divided - Jon basically betraying her for his brother as well as to stop the armies of the dead all with one blow per say. Dany believes Bran is too far gone and so attempts destroying him along with the rest of the armies anyhow, causing the divide to become a war between ice and fire, where neither side is completely the good guys, nor the bad guys at this point. In this battlem the crypts will become destroyed by Danys dragons - in a battle between them and the Night King and his resurrected dragon, and once the crypt and the bodies within are burnt and gone, the Other will be released. Bran will at this point be able to warg out of the Night King, dropping the armies instantly, as the Other no longer needs the Night King to free him (the Others agenda in the first place - known by the first man and the reason the first man went to find the children in the first place!) so, Dany, Jon, their remaining forces, the children that remain, and the now returned Bran must stop the Other or else winter will never become spring, and will always remain until the world freezes over. At this point, i couldnt say what may occur exactly, but can say that in the end Bran will be able to warg into the Other itself, and essentially become winter, and thus controlling the Other and its godly forces (with an inner struggle) but Bran will win out with the help of Dany and Jon and the others, and he will rescind winter, allowing spring to come forth and ending the Others deadly winter forces. Thus, again, as in the ancient days, this will occur at winterfell, where winter has fallen before when the Other was trapped and bound in the crypts by Bran the Builder and the children.