So, the end episodes in the series are obvious to me. The WWWW pass the wall crushing everybody with his ever growing zombie army, then in the last moment when everyhing seems lost and Jon is almost heroically defeated, Sam, aka the library fat rat, find an ancient book at the library explaining dragon fire = WW toast, send a letter to Daenerys (i think they have 24h express crows or something) so she send her three flying pets northward and the WWWW are turned into ashes in an eyeblink. Daenerys is claimed as queen and savior of the whole world, Jon is promoted to Hand and everybody is happy forever.
Nice, isnt it?