|Although this article is based on canonical information, the actual name of this subject is pure conjecture.
Last Hearth is the seat of House Umber and the northernmost castle before reaching the Wall, thus making it the closest settlement to the Wall. As Jon Snow previously predicted, Last Hearth was the first major obstacle in the path of the White Walkers and their army of the dead since breaching the Wall .
Following the death of Smalljon Umber at the Battle of the Bastards, his son Lord Ned Umber swears allegiance to House Stark. He is instructed by the Starks to return to the castle and rally the bannermen sworn to his house.
The forces of House Umber clash with the army of the dead led by the White Walkers, and are defeated at Last Hearth.
Sometime after the battle, a group of Free Folk and Brotherhood Without Banners led by Tormund and Lord Beric Dondarrion, makes it to Last Hearth after escaping the fall of the Wall. They find blood but no corpses in the courtyard of the castle. Going deeper into the dark castle, they stumble upon acting Lord Commander Eddison Tollett and the survivors of the Night's Watch.
The combined group finds Ned Umber dead inside the castle, pinned against the castle walls with a group of severed limbs in a spiral formation around his body. Beric deduces that it is a message sent by the Night King. Tormund notes that, with them at Last Hearth, the army of the dead is between them and Winterfell, and they will have a difficult time giving chase on foot. Edd says that his own group rode from Castle Black and they can double up on the horses. While Tormund is turned around, the dead Ned Umber reanimates as a wight and slashes at Tormund with a knife, emitting a terrifying screech. Beric quickly burns the wight with his flaming sword, and the entire spiral symbol is lit on fire.
In the books
In the A Song of Ice and Fire novels, no equivalent battle has occurred. The TV show has surpassed the timeline of the books, so it is unclear if an equivalent battle will occur.