The stories that make up "Trey of Swords" (Witch World #7) take place in Escore, the weird sister-state of witch-ruled Estcarp that lies to the forbidden East in "trembling balance between the forces of Light and those of the Dark."
Each story is roughly sixty pages in length and the first two, "Sword of Ice" and "Sword of Lost Battles" are narrated by Yonan, a border guard of Estcarp who is called to the defense of Escore by Kyllan Tregarth.
(Many of the characters in "Trey of Swords" will already be familiar to Witch World readers, most notably the warrior Kyllan Tregarth, and Dahaun, mystical Lady of Green Silences).
Yonan, an indifferent warrior at best is injured in a fall in the mountainous heights surrounding Escore's Green Valley. While separated from his patrol by a storm, he discovers the hilt of an ancient sword---an artifact of the vanished Great Adepts of magic.
Oh, no! All WW fans know that ancient artifacts are better left untouched. But Yonan feels a compulsion to rescue the sword hilt from its imprisoning stone, and so the original wielder of the Sword of Ice is able to reincarnate himself within Yonan. Yonan-now-Tolar forges a magical blade for his sword, rescues his friend Uruk of the Ax from a pillar of ice, and together they hurtle back through time to refight the Lost Battle of Witch World.
Before they bid farewell to the present, Yonan-now-Tolar and Uruk rescue Yonan's childhood companion, the untrained witch, Crytha from the filthy, claustrophobic burrows of the Rasti.
Crytha then narrates the third story of the trilogy, "Sword of Shadows."
An untrained witch is a very dangerous thing to be in Escore: a vessel waiting to be filled with the wrong kind of magic---which is exactly what happens to Crytha. She is put under a strong compulsion to obey an evil female magician named Laidan, who is plotting to reincarnate her lover, an adept of the darkest shadow who originally perished in the Lost Battle. (Evil females in Norton stories are easily identified by their scarlet lips and wanton behavior.)
How Crytha manages to foil the adepts of the Dark, with unexpected assistance from one of the Great Ones who had withdrawn from Witch World after the Lost Battle is the essence of "Sword of Shadows."
My only reason for withholding a star from my review is the very loosely constructed plot of "Trey of Swords." I never did quite comprehend why the Lost Battle of Witch World had to be refought. A more favorable outcome to the ancient battle didn't seem to change anything in 'modern-day' Escore---at least not by book's end. The blurb on the cover states that "the fate of witch world hangs in the Balance!" but I've read "Trey of Swords" at least twice now and still haven't figured out what sort of awfulness fate had in store, if Yonan and Crytha hadn't done their thing.
Read "Trey of Swords" because Norton tells an engrossing story of Good versus Evil magic in fabled Escore.