This is a siege film that understands what a siege actually costs. Helm's daughter inherits a fortress and learns immediately that strategy means nothing against the weight of bodies at your gate. The Dunlendings aren't faceless invaders, they're led by a man hunting blood for blood, which means every defense is a choice to kill someone's son for your own. Animation holds the horror of that math without flinching. You watch a fortress break not because the walls fail, but because the people inside them do.

Nearly two centuries before the events of the original trilogy, Helm Hammerhand and his people come under sudden attack. Wulf, a cunning and merciless Dunlending lord, strikes at them to avenge his father's death. Driven to make a bold last stand in the old stronghold of the Hornburg, Helm and his people prepare for a fight against an enemy bent on wiping them out entirely. As their situation grows ever more dire, Helm's daughter Hèra must find the resolve to lead the resistance. The result is an animated fantasy film of action and drama about courage under siege.