Welcome to the finale of the Siegfried Campaign!
After Siegfried defeats Hagen, he meets Gunther's sister: Kriemhild in a moonlit garden. After complimenting Siegfried on his win, Siegfried and her briefly discuss Gunther's plan. She tells him to follow his heart, and to make sure he will be able to live with the consequences of whatever choice he makes moving forward.
The next day a messenger arrives weary and distraught. He reports that the Saxon kings Ludgar and Ludgast have besieged Burgundian settlements along the Rhine. Siegfried, Hagen, and the other Burgundian knights then launch a counterattack, razing Saxon lands and are now waiting for the two kings to exhaust their forces in order to march into their lands and capture these two savage war lords.
After dealing with this threat King Gunther wants Siegfried to help him on the quest he had spoken about before:securing the Valkyrie known as Brunhild to his cause.
When they arrive they are met with the utmost hospitality as per custom. Queen Brunhild sets three trials for Gunther to complete: spear throwing, a race within the sacred stone casting, and finally: a duel until first blood or submission. The queen is so formidable, even Siegfried wonders if he may beset her.
After everything is said and done, the plot that Siegfried had taken part in was revealed by Brunhild years later. Hagen, wanting to leverage this to gain political power, had gathered allies in order to bring an end to the legendary dragonslayer.
Important Note: In Ch 4 try not capture the enemy estates. This will likely aggro either of the enemy's dragon and they will burn your army to a crisp. Of course you can still do this and you still can win the mission, however it will make it much more difficult than it needs to be.