The god Wotan gives the young Prince Sigmund of Valhalla and his sister Brunhilde, the leader of the Valkyries, the task of defending the Petrified Forest. This is threatened by the Vikings (led by the aggressive Hunding), who plans an invasion of the forest in search of the secret treasure of the Nibelung, the possession of which gives one unlimited power. After crossing the border and invading Valhalla, Hunding finds an ally in the daughter of one of Sigmund's loyal followers, Erika, who is embittered by unrequited love. She helps the Vikings raid the camp of the Valhalla residents and kill many warriors. Sigmund swears vengeance and pursues them with the remaining men. However, thanks to other traitors in Sigmund's ranks, Hunding succeeds in capturing him and his fiancée Siglinde, Erika's sister. At the end, Sigmund escapes and, with the help of the Valkiries, succeeds in stopping the invaders and defeating Hunding in a duel.