Plot summary of chapter: We have two characters, Arek of Estre and Therem of Stok. They are both heirs to their lands, and their peoples have been fighting for generations over where the border between their lands are. One night Arek falls through thin ice, but he's able to pull himself out of the freezing water and get to a house on disputed land.
Therem was all alone in that house and nurses Arek back to health. Arek says to Therem "We are mortal enemies [...] I would swear kemmering with you" (126). (Swearing kemmering is their form of marriage.) Shortly thereafter Therem's friends arrive and one of them recognize Arek as their enemy. Without warning, Arek is suddenly killed.
But Therem has already gotten pregnant by Arek, and after giving birth in secret names the child Therem and gives the baby to Arek's father, who is still the lord of Estre, saying that it was Arek's child. Once Therem of Estre is fully grown he is ambushed by rivals (who, like little Therem, are of Estre) but he manages to kill them all. Not without being injured, though. He manages to make his way to a deserted house on disputed land.
This is the same house where his parents met, and Therem of Stok finds him there and treats his wounds. Therem of Estre says to Therem of Stok"We are mortal enemies. Yet I have never seen you before. [....] I will vow peace with you" (129).
Therem of Estre became the lord of his lands when his grandfather died. And, "Within the year he ended the old feud, giving up half the disputed lands to the Domain of Stok. For this, and for the murder of his hearth-brothers [those who had tried to kill him], he was called Estraven the Traitor" (129).
Parallels in land issues
In current events in this book we have a Therem of Estre (I will call him Therem of Estre II, although he is never called that in the book), and another land dispute. Therem of Estre II's solution to the current land dispute is to move his people out of the way and give up the land. He figures that losing land is better than watching good people die.
Naturally, this isn't a decision that makes him very popular. But it is one thing that he has in common with the old "traitor" Estraven, and something which might have driven him out of his land.
Parallels in kemmering
Just like I'm calling the current Therem Therem of Estre II, I will call Therem of Estre II's old kemmering Arek of Estre II.
We know that Therem of Estre II and Arek of Estre II were had kemmering together, and that Arek bore Therem a child. I've already mentioned before that I think they as good as swore kemmering to each other, even though full siblings aren't supposed to, and that this ties into another story told. If so, and if Arek killed himself because he could not properly swear kemmering to Therem after having a child together, then that could be a parallel between Therem of Estre II and the first Therem of Estre who was called a traitor in part "for the murder of his hearth brothers" (129).
I'm still trying to figure out parallels between the first Arek of Estre and Arek of Estre II. I don't think le Guin would have given them both the same name without good reason.