Heroes Chronicles: The World Tree opens with the immortal hero Tarnum haunted by a recurring dream commanding him to protect something called the World Tree. Following the vision northeast for hundreds of miles, he reaches an ancient cave and joins the remnants of a barbarian tribe charged with guarding it. Necromancers have invaded the cavern, and Tarnum assumes the Ancestors sent him to drive them out.
Five local shamans teach him that the World Tree sustains all living things, though its exact location remains unknown. Deeper in the cave system he encounters a barbarian faction allied with the necromancers — followers of Vorr, one of the three divine Ancestors who has become consumed by war-god fury. Their mortal king, Targor, models his rule on Tarnum's own brutal past as the Barbarian Tyrant.
Determined to break Vorr's hold over these people without more bloodshed, Tarnum sends his second-in-command, the ogre Grumba, to recover the Pendant of Total Recall — an artifact that can force Targor to experience centuries of Tarnum's own suffering and shame. An elven druid named Nilidon then reveals the truth: the vast tunnel network around them is the World Tree itself, also called the Roots of Life.
The Pendant is found and delivered. Targor witnesses Tarnum's past, renounces Vorr, and dies fighting him. Vorr abandons his destructive campaign, and the surviving barbarians destroy the remaining necromancers. With the World Tree safe and beginning to heal, Tarnum leaves to find Vorr himself.