Explorer Brann Bronzebeard's expedition into the colossal titan structure of Ulduar unearths a revelation that overshadows the military campaigns sweeping across Northrend: the fortress serves as an ancient containment vault for Yogg-Saron, an Old God whose corrupting presence permeates the frozen continent itself. Recognizing the existential threat, brave bands of Alliance and Horde warriors join forces to breach Ulduar's defenses and confront this primordial evil directly. As the champions delve deeper into the complex, Yogg-Saron assails them with disturbing visions—fragmented glimpses of the past, present, and future that hint at ancient artifacts, fallen kingdoms, and the dark destiny awaiting the Lich King himself.