With the spectacular showing of Stark reunions, dragon fire, Daenerys kicking ass, and Jaime’s aquatic cliffhanger, we’re all pumped to see what happens next on Game of Thrones. Though the trailerfor “Eastwatch” picks up with Dany and Drogon looming over a beat army, the namesake for the episode is a location much farther North.
Eastwatch-by-the-Sea is, as the name implies, the easternmost castle along the Wall. It sits on the shore by the Bay of Seals. The Night’s Watch keeps several galleys at Eastwatch, including some larger ships that are able to cross the Narrow Sea. The Bay of Seals is patrolled by these galleys, mostly because smugglers often trade weapons to Wildlings there. There have been some reports that fishermen near Eastwatch have seen White Walkers.
Over the centuries, the numbers at the Night’s Watch have fallen drastically and now it’s just a shadow of it’s former self. As a result, the Night’s Watch has abandoned most of it’s castles and it now has only 3 castles that are properly manned, out of the 19 castles that are located along the Wall – Castle Black, The Shadow Tower and Eastwatch-by-the-Sea.
In the books, the commander of Eastwatch is Cotter Pyke and the maester is former archmaester of the Citadel named Harmune. Viewers of the show have not met either of these characters. In the show, Maester Aemon sends Daeron to Eastwatch to report to Borcas, who is the head steward over there. Also, the then Lord Commander, Jeor Mormont tells Jon Snow in the 1st season that the men at the Eastwatch came across 4 Wights in the snow, but they had the sense to burn the bodies.
Eastwatch has hardly been mentioned throughout the series, with few mentions over the years. In the 2nd season, Tyrion Lannister sends the commander of the City Watch, Janos Slynt on a boat headed for Eastwatch-by-the-Sea, while in the 3rd season, when Jon Snow is with the Wildlings, he tells them that only 3 castles are manned by the Night’s Watch. In season 5, Stannis advises the newly appointed Lord Commander, Jon Snow to send Ser Alliser Thorne to Eastwatch, but Jon Snow decides to keep him at Castle Black and makes him the First Ranger.
And now, Jon said in the beginning of the season: that the Wall has not been properly manned in centuries, and the closest castle to Hardhome – where we last saw the White Walkers and the army of the dead – is Eastwatch. That’s why Jon Snow sent Tormund Giantsbane and the Wildlings there to man the wall at that point.
In the same episode (“Dragonstone”), we also see the Brotherhood without Banners riding north. The Hound sees a vision in the flames that points to Eastwatch, which means that’s likely where the Brotherhood is traveling as well.
Back to what we know from the brief trailer: it ends with Jon telling Daenerys that Bran has seen the army of the dead at Eastwatch. Bran seems to have warged into Ravens and flown there to check things out. After confirmation that, yes, the untold numbers of the dead are on their way, Bran sent another Raven to warn Jon at Dragonstone.
Daenerys seems quite occupied with the war with Cersei, and since Jon has not yet bent the knee it’s not clear that Dany will help him, or at least not yet. Jon is probably anxious to return to the North, however, and with or without help from the Mother of Dragons, he will probably be returning home to prepare for what’s to come.