(Spoiler Alert: Major spoilers for the May 22, 2016 episode of "Game of Thrones" are found below. If you haven't seen the episode and don't want to be spoiled, stop what you're doing and leave now.)
Wow, that was quite a humdinger of an ending to Sunday's episode of "Game of Thrones," "The Door." Emotions ran wild, and most of us got the gist of what happened there but some of the specifics might be tough to grasp in retrospect.
Have no fear. We're going to walk you through exactly what happened there, and hopefully it won't inspire too much trauma reliving those events in painstaking detail.
The big moment, as you know, was the death of Hodor at the hands of the White Walkers' undead army as he held them behind the door to the Three-Eyed Raven's cave so Bran and Meera could escape. But let's take a big step back to the beginning of this hectic chain of events.
What's going on at the start of this sequence is Bran and the Raven are again visiting Winterfell decades earlier via a time travel "dream," and we see Bran's grandfather Rickard giving a young Ned Stark a pep talk before sending him away. Also present is a young Wyllis, who we know better as Hodor. Back at this time Hodor is a normal boy who can say many things other than "Hodor."
Meanwhile, the Night's King and several other White Walkers have brought an army of undead to the Three-Eyed Raven's cave. The Children of the Forest attempt to hold them off outside with magic grenades and a barrier of fire, but it doesn't accomplish much aside from briefly stalling their progress.
This mass of bad guys manages to get into the cave, while Bran and the Raven are still having their time-travel dream. Hodor, as he's wont to do in dangerous situations, sits in the corner holding himself saying "Hodor" over and over again.
Meera and the Children fight the undead, but they need to flee or else they'll be slaughtered. So Meera screams at Bran that they need Hodor, and Bran wargs into him, taking control as he'd done a few times in the past. However, Bran doesn't leave the dream. He multitasks it.
So Hodor, controlled by Bran, escapes from the cave with Bran and Meera, but the tide of undead requires that Hodor personally bar the door to the cave while Meera drags Bran away. Meera yells, "Hold the door!" at Hodor repeatedly -- and with Bran still in the dream, Meera's command is passing into the past. The young Hodor hears it.
Because of the weird time bridge that is Bran connecting the younger and the present-day Hodor, the younger version goes into a seizure and begins repeating, "hold the door," over and over again, eventually mashing the phrase together into "Hodor."
This all happens because Bran's trips to the past are more than just dreams -- he's really going there. As we saw in a previous one of his flashbacks, Bran is able to in some way affect the past -- he shouted at a younger version of his father Ned, who actually heard it, though he couldn't see Bran.
So it's not merely a coincidence that Bran traveled back to the moment when Hodor became Hodor, unable to say anything other than what would become his nickname. Bran actually caused it, unwittingly. He also set Hodor on his lifelong path to that moment in the present, where he died saving Bran and Meera. He wasn't changing the past, but rather causing it. This is always how Hodor became Hodor. It's a time loop!
When Bran shouted at his dad in that previous flashback, the Raven discouraged it, telling him he couldn't change the past. And maybe that's true. But it doesn't mean he can't have a hand in past events -- in fact, it probably means he already has, and we just haven't seen it yet.
This is a fascinating new wild card for the big picture in "Game of Thrones." At the end of "The Door," Bran is forced to take the place of the Three-Eyed Raven, so his journeys to the past surely aren't at an end. And just as surely his shenanigans affecting past events, either purposely or not, also aren't over.
Some fans have already made guesses as what form some of those shenanigans might take. Check out the gallery of fan theories below for several really intriguing theories about Bran's potential time travel influence in future episodes.
Watch the 'Hold the Door' scene again below.