Siegfried: Well, I think its about time for me to be taking Kriemhild home to my kingdom.
Gunther&co.: But. . .whyyyyyy?
Siegfried: Dudes, I've been here for like three years now. Its time to go home.
Gunther & co.: We'll give you presents if you stay a bit longer!
Siegfried: Goodbye, Gunther & co.
So, Siegfried takes his beautiful new wife home to his kingdom, his father immediately steps down and hands his crown over, and within ten years, Kriemhild gives birth to a son, whom they name Gunther. Why they wanted to name their son after that dumbass, I'll never know, but so it was.
At the same time, Brunhild gives birth to a son, and they name him Siegfried. (if you thought things were confusing before. . .. )
Brunhild, over the past ten years has, unsurprisingly, grown quite bitter. She is jealous of Kriemhild's happiness with Siegfried, and is upset by the fact that the other royal couple didn't send so much as a postcard from their honeymoon trip.
(also, she misses her girlfriend)
Sayeth Brunhild of Kriemhild:
“Thy sister’s lofty bearing / and all her courtesy,
Whene’er I think upon it, / full well it pleaseth me,
How we did sit together / when erst I was thy spouse!
Well in sooth with honor / might she the valiant Siegfried choose.”
(sounds like a girlcrush to me)
So, Brunhild whines to her husband about it, and they plot to lure Kriemhild and Siegfried back to Worms with a feast (at least its not a play).
King Gunther's messengers arrive, and proceed to relentlessly guilt Siegfried into agreeing to the visit.
Apparently medieval women pack like women today: "Carrying-chests full many / for the way they made ready".
Leaving behind their son, Kriemhild and Siegfried set forth to other-Gunther's court. Oh, and BAD THINGS ARE GOING TO HAPPEN (medieval foreshadowing is about as subtle as a baseball bat to the head).
The visitors are greeted warmly. Especially warm is the greeting Brunhild gives Kriemhild:
"oft her glances / Brunhild was seen to cast
Upon the Lady Kriemhild, / for she was passing fair.
In lustre vied her color / with the gold that she did wear"
AAAAAND Kriemhild puts her foot in it, saying to Brunhild:
“Such spouse in sooth have I,
That all these mighty kingdoms / might well beneath his sceptre lie.”
to which Brunhild responds:
“How stately thy spouse be,
Howe’er so fair and worthy, / yet must thou grant to me
Gunther, thy noble brother, / doth far beyond him go:
In sooth before all monarchs / he standeth, shalt thou truly know.”
(*snicker* as if)
this devolves into:
"My husband is better!"
"No! Shut up! Mine is!"
So, to prove her point, Kriemhild goes and plays dressup, hoping to awe Brunhild into submission with fine clothes (hell, it worked last time).
The arguement rages, until finally Kriemhild drops the bomb:
“for that thy body fair
First was clasped by Siegfried, / knight full dear to me.
In sooth ’twas ne’er my brother / won first thy maidenhead from thee."
OHO, things just got nasty. To prove that Siegfried had lain with Brunhild that night, Kriemhild shows her the ring and the girdle he had stolen from Brunhild (knew that would come back to bite him in the ass).
Siegfried and Gunther unite valiantly to attempt to preserve their lie, but the damage has been done. Half the castle is up in arms, wanting Siegfried dead for laying with their queen, the other half insist he doesn't deserve it.