Wotan, chief of the gods, and the dwarf Alberich contend for mastery of the world. Wotan had Valhalla built by the giants Fasolt and Fafner, to be a fortress for the gods. Alberich the Nibelung forswore love - something Wotan could never have done - and thereby met a condition which earned him power and riches. From the gold out of the Rhine he had his slaves forge the Nibelung hoard, including a ring and a magic cap. These treasures were snatched from him by Wotan, who, having acquired them wrongfully, was forced in his turn to hand them over to the giants. The curse that Alberich laid on the ring drove Fafner forthwith to kill his brother; then, with the aid of the magic cap, Fafner turned himself into a dragon and now lies in a cave, watching over the hoard.