Castle Black

The castle runs along the south face of the Wall, between Queensgate and Oakshield, at the point where the Kingsroad ends. It has no wall facing south — it never needed one. Many of its stone towers are half in ruin, and only a few are still properly used: the Lord Commander's Tower, the King's Tower right against the Wall, the leaning Hardin's Tower, the tall and crumbling Tower of the Spear, the sturdy Guards' Tower by the road. Underneath it all run the wormways, tunnels that in winter are the only way to move between buildings without freezing.

That's where Lord Commander Jeor Mormont lives, and where recruits from all over the realm train. At its height the castle held more than five thousand men; by the time Jon Snow walks through its gates, barely six hundred are left. One night, when Jon fights off the wight of a dead brother inside the Lord Commander's Tower, fire takes out the building's top two floors.

Mormont doesn't stay put for long. He leaves the castle with two hundred of his men to head out beyond the Wall, on an expedition meant to find out what's going on with the wildlings and with the wights that have started to appear.

Of the roughly six hundred brothers holding the castle, two hundred walk out the gate — one in three. Castle Black settles into a wait with the thinnest garrison it's had in a long while, with no way of knowing how long the absence will last.

The fortress hadn't seen an attack like this in generations. The Magnar of the Thenns strikes from the south and sets part of the buildings on fire. Donal Noye, the armorer, stops him by burning the lower stretch of the wooden stair that climbs the Wall, taking a good number of the attackers down with it.

Almost at the same time, Mance Rayder throws his army against the gate from the north. Giants and mammoths manage to break down the outer gate, solid oak reinforced with iron, but not the two doors behind it. Noye dies defending the passage.

Stannis Baratheon's arrival with his troops turns the siege around: he defeats the wildlings still standing and settles in at the castle with his people. The election that follows brings a new Lord Commander, Jon Snow, the 998th to hold the title.

With the battle won, the inside of the castle changes shape. Stannis moves into the King's Tower, right by the Wall. Jon leaves his old room for the chambers that used to be Donal Noye's, behind the armory, and sets the builders to work day and night repairing the wooden stair.

As Lord Commander, Jon orders Janos Slynt to take charge of one of the abandoned castles along the Wall. Slynt refuses. Jon beheads him on the spot, in front of everyone, for disobeying a direct order.

Jon keeps unsettling the black brothers with his choices: he sends Val to talk to Tormund Giantsbane, and out of that meeting comes a fragile alliance between the Watch and the wildlings. He lets them settle by the Wall and offers their fighters a chance to help defend it against the Others. Meanwhile, Melisandre burns the man who's been posing as "Mance Rayder".

The red priestess tells Jon she sees in the flames a girl riding into Castle Black on a horse about to collapse. Jon is sure it's Arya, fled from the Boltons, but the girl who arrives is Alys Karstark. Melisandre also warns him she sees him surrounded by knives in the dark. Jon doesn't put much stock in it.

Weeks after Stannis marches on toward Winterfell, a letter reaches Jon from Ramsay Bolton, signed "Bastard." It claims Stannis has been defeated and Mance Rayder captured, and demands Jon swear the Night's Watch's loyalty to House Bolton if he wants to save his men.

Jon decides to act, even if it means breaking the vow he swore on joining the Watch. The decision doesn't sit well with the castle's senior men: first Ser Patrek turns up murdered, and then Jon himself is stabbed several times by Bowen Marsh and other black brothers.