This trilogy has apparently been out of print for a while.  I had never heard of it until it was recommended as a great read by several of my site visitors.  Went looking for it, but was unable to find a copy.  Fortunately, in 2003 the Science Fiction Book Club published all three books in a single volume and I was finally able to read it.  And what a story it is!  Told completely from the point of view of the unicorns, it is filled with mysticism, adventure, courage and faith.

Here's a brief synopsis of the story based on the description on the book jacket:

...My tale touches how the Firebringer came to be born among the unicorns,

and what his coming meant to Aljan, son of Korr...

Forty generations past (400 years), wyverns invaded the unicorns' rightful lands in the Hallow Hills of the balmy north.  Under the guise of friendship, their leader befriended the unicorns' aged king, using sorcery to addle the old stallion's wits and blinding him to their schemes.  In a treacherous ambush, wyverns stung to death most of the unicorn warhost, and slew nearly all the rest with fire.  Only a few escaped, fleeing coldward—south—across the Plain.  Coming at last upon a vast, deserted vale, the unicorns claimed it as their new home in exile.  There the tribe awaits the coming of the Firebringer—a unicorn who possesses the secret of fire and will one day appear to lead the children of the moon back to their sacred lands as foretold in an old song:

"The silver moon rode on his brow,

And a white star on his heel."

Jan, the headstrong prince of the unicorns, has often heard the story of how the evil wyverns drove his people from their ancestral homes.  It is a story that haunts him even as he waits impatiently for the great expedition that will mark his passage into adulthood.  He is nearly six years old, but still counted among the colts.

Though his rebellious, reckless spirit sorely vexes his stern father, Korr, Jan is allowed to join the Pilgrimage.  With his childhood friend, Dagg, and a female warrior, Tek, by his side, Jan encounters dangers he'd only heard of in songs—the outcast Renegades, the blue-coated wyverns and the great winged gryphons, whose sacred hunting grounds Jan's tribe has unknowingly occupied.  With each encounter, he learns more truths about his people, his enemies, the wider world, and his own destiny.

Despite Korr's objections, Jan and Tek declare their love—just before a storm sweeps Jan out to sea.  Washed up on a distant shore, Jan becomes the revered prisoner of a race that teaches him the secrets of fire.  Can Jan escape to bring this knowledge back to the unicorns...and restore peace to his world?