Spoilers for Game of Thrones below.

Tonight’s episode of HBO’s Game of Thrones, “Battle of the Bastards”, promises to be the centerpiece of already consistently excellent 6th season that, if rumors (which we won’t spoil) are true, means dramatic changes for the show’s status quo going into the season finale and what looks like the final seasons 7 and 8. For those of you who’ve stuck with the show for 6 seasons, you know what that title means: Jon Snow (Kit Harington) and Ramsay Bolton (Iwan Rheon) will finally be mixing it up for control of the north.

Why does this matter? The series has been focused on the various noble and commoner (smallfolk) factions grasping for power as the kingdom of Westeros descends into tragic anarchy, beset by one disaster over another. But the real threat facing the world of Game of Thrones is the army of ice zombies called the White Walkers. Led by a possibly undead or immortal ghoul called the Night’s King, they’ve been massing north of the giant wall separating Westeros from the vast frozen wasteland, waiting for winter to descend so they can invade.

So far, Jon Snow is the only main character on Game of Thrones who has taken that threat seriously, having gone up against them personally in last season’s stand out episode “Hardhome,” which by the way was directed by Miguel Sapochnik who also directs “Battle of the Bastards” as well as next week’s season finale. As winter, which can last years in the show’s universe, is fast approaching, controlling the north and rallying the various people in it behind him is a crucial step Jon’s preparation for that invasion.

It’s also personal, however. Jon Snow, ostensibly the bastard son of Lord Eddard Stark (played by Sean Bean and offed in the first season), has watched helplessly for years as his family has been variously murdered, kidnapped, assassinated, etc etc. The last straw happened last season, when his half-sister Sansa Stark was married to and then brutally raped and abused by… Ramsay Bolton, vicious sociopath and legitimized bastard son of Roose Bolton. Sansa managed to escape and is now reunited with Jon at the Wall. Meanwhile Roose, by the way the man who betrayed Jon Snow’s half-brother Robb “The King In The North” Stark back in season 3 at the Red Wedding, was murdered by Ramsay earlier in the current season. Ramsay then assumed his title and sent Jon Snow a terrifying threatening letter demanding he return Sansa, or else he’ll kill Jon and Sansa’s younger brother Rickon Stark, captured in the second episode of season 6.

Unable to do anything about it because of his oath to the Night’s Watch, which requires celibacy and the renunciation of all titles and ties to the normal world, Jon was freed from that oath thanks to his assassination last season. Yeah, he was brought back from the dead, but the oath says a Night’s Watch member’s tenure “shall not end until my death.” Resurrected or not, he fulfilled that requirement and is now allied with Sansa, and the pair have been traveling the north attempting to gain allies to their cause over the last few episodes.

Tonight, all of these threads converge as the two sides face off. The episode begins at 9 PM Easterm/6 PM Pacific, and Deadline will be posting our wrap up shortly after. Check back after 7 PM for the blow by blow.