The legend begins in the cold, mist-shrouded halls of the Giukings, where King Giuki and his formidable Queen, Grimhild, ruled over the Burgundians. Into this court rode the greatest hero of the age, Sigurd the Volsung, the slayer of the dragon Fafnir and the possessor of the cursed Rhinegold. Sigurd was a man of incomparable stature, riding the horse Grani, a descendant of Sleipnir, and carrying the shattered then reforged sword Gram. Before arriving at the court of the Giukings, Sigurd had ascended the mountain Hindarfjall, where he passed through a ring of flickering fire to awaken the Valkyrie Brynhild from an enchanted sleep. Upon that mountain, the two had exchanged vows of eternal fidelity; Sigurd had given her the ring Andvaranaut as a pledge of his love, and they were bound by oaths that neither expected to break.
However, the threads of fate are often woven by the hands of those with darker intentions. When Sigurd arrived at the Giuking court, he was received with the highest honors. King Giuki saw in Sigurd a powerful ally, but it was Queen Grimhild who saw a way to cement her family’s legacy forever. Grimhild was a woman skilled in the ancient and terrifying arts of seidr, a form of magic that allowed her to perceive the hidden paths of the mind and influence the hearts of men. She looked upon Sigurd and saw not just a hero, but a treasure that must be anchored to her house. She desired that Sigurd marry her daughter, the beautiful and gentle Gudrun. Yet, she knew that as long as the memory of the golden-haired Brynhild remained in Sigurd's heart, he would never look upon another woman with desire.
Grimhild withdrew to her inner chambers, where she brewed a potent draught. This was no ordinary ale; it was a mixture of honey, herbs, and dark incantations designed to cast a veil over the soul. It was the 'Ale of Oblivion,' intended to wash away the past and leave the mind a blank slate upon which new loyalties could be written. During a grand feast held in Sigurd’s honor, where the mead flowed freely and the skalds sang of ancient battles, Grimhild approached the hero. With a smile that masked her cunning, she offered him a horn filled with the enchanted liquid. Sigurd, suspecting no treachery from his hosts and brothers-in-arms, took the horn and drank deeply.
As the liquid passed his lips, the transformation was instantaneous and terrifying. The memories of the mountain Hindarfjall, the flickering flames, and the face of the Valkyrie Brynhild began to dissolve like morning mist under a harsh sun. He remembered his name and his deeds, but the emotional core of his life—his bond with Brynhild—was severed. The love that had burned so brightly was replaced by a hollow void, which Grimhild quickly sought to fill. When Sigurd looked up from the empty horn, his eyes fell upon Gudrun, and through the haze of the magic, she seemed the most desirable woman in the world. He forgot that he had ever loved another. He forgot the oaths he had sworn upon the mountaintop. In this state of magical amnesia, Sigurd accepted the hand of Gudrun in marriage, and the two were wed with great pomp and celebration.
This act of treachery, however, was only the first step in a larger tragedy. Sigurd’s arrival had brought great prestige to the Burgundians, and King Gunnar, the eldest son of Giuki, now sought a bride worthy of his station. He had heard tales of a magnificent queen who lived within a castle surrounded by a wall of fire, a woman who had sworn to marry only the man brave enough to ride through the flames. This woman was, of course, Brynhild. Gunnar, unaware of the full extent of Sigurd's prior history with the Valkyrie, asked his new brother-in-law to accompany him on the quest to win her hand. Sigurd, his memory still suppressed by Grimhild’s potion, agreed to help Gunnar as part of their sworn brotherhood.
When they reached the wall of fire, Gunnar attempted to ride his horse through the blaze, but the animal recoiled in terror. Even when Gunnar mounted Sigurd’s horse, Grani, the beast refused to move for anyone but its true master. Seeing that Gunnar could never breach the fire, the heroes turned to the dark magic of Grimhild once more. By using a spell of shape-shifting, Sigurd and Gunnar exchanged appearances. To any observer, Sigurd now looked exactly like Gunnar, and Gunnar looked like Sigurd. In this borrowed form, Sigurd spurred Grani forward. The horse, recognizing his master despite the illusion, leapt through the wall of roaring flames.
Inside the circle of fire, Sigurd (appearing as Gunnar) found Brynhild. She was astonished and devastated that a man other than Sigurd had breached the flames, but she was bound by her own vow to marry whoever achieved the feat. Sigurd stayed with her for three nights, but to remain honorable to his wife Gudrun, he placed his cold sword Gram between himself and Brynhild in their bed. Brynhild, believing she was being wooed by Gunnar, eventually agreed to the marriage and returned with him to the land of the Burgundians. It was only after the wedding of Gunnar and Brynhild was finalized that the magic began to unravel. The sight of Brynhild in his own hall caused the potion's grip on Sigurd's mind to slip. Too late, his memories returned. He realized the magnitude of the deception and the tragedy he had unwittingly participated in, but he was bound by his oaths to Gunnar and his marriage to Gudrun. He remained silent, hoping to avert a catastrophe.