Part one of the film based on the German myth of the Nibelungen: Young Siegfried was trained be master Mime and is already a skilled armourer, when he travels to Worms to see King Gunther and the King′s sister Kriemhild. On his way, he is attacked by a dragon. Siegfried slays the beast and bathes in its blood, thus becoming invulnerable – except for small spot between his shoulders.
Siegfried then retrieves the treasure of the Nibelungen, arrives in Worms as a hero, and woes Kriemhild. Thanks to a cloak which makes him invisible, Siegfired secretly assists King Gunther in a ritual fight with his wife-to-be Brunhild. When the jealous Brunhild, whose love for Siegfried was unrequited, later learns form Kriemhild – who is to marry Siegfried – about this, she demands from King Gunther that Siegfried should be killed. While on the hunt, Siegfried is murdered by Gunther′s loyal warrior Hagen von Tronje. Bent on revenge, Kriemhild swears to avenge the death of her husband while a guilt-ridden Brunhild commits suicide.