In The Hawk's Gray Feather Taliesin recounts his youth on the planet Gwynedd, and the beginnings of his lifelong friendship with Arthur of Arvon, destined to be the greatest king in both Keltic (and later Earth) history (at least until his descendant Aeron comes along 1500 years later).
The Hedge of Mist concludes the Arthurian trilogy with a unique Grail quest and an epic battle to reclaim the soul of Keltia.