More than a thousand years ago the armies of the Arcosian Empire, led by Mornhavon the Black, crossed the great sea and tried to conquer the land of Sacoridia using terrible dark magic. Eventually Mornhavon had been captured, and his evil spirit imprisoned in Blackveil Forest, protected by the mighty D’Yer Wall; and in the centuries since the war’s end, knowledge of the working of magic had disappeared from Sacoridia.
Karigan G’ladheon was now a seasoned Green Rider—a member of the magical messenger corps of the king. But during her first year as a Rider, a rogue magician had cracked the D’Yer Wall. The spirit of Mornhavon, sensing the weakness, had begun to wake, seeking vengeance. Karigan had managed to transport the spirit of Mornhavon into the future, buying valuable time for her king and country. But how far in the future was Mornhavon now? There was no way to tell.
And though Karigan and her fellow Riders scoured the land searching for lost magical knowledge, they were unaware of a threat to their kingdom that lay far closer: the descendants of ancient enemies had spent generations honing their powers of dark magic—a force against which the Sacoridians had no defense. The High King’s Tomb is the thrilling third installment of the Green Rider series.

Karigan G’ladheon had been a Green Rider, one of the king of Sacoridia’s elite magical messengers. In the messenger service she had been caught up in a world of deadly danger, and though she had defeated the Eletian who cracked the magical D’Yer Wall—which had protected Sacoridia for a thousand years from the dark influence of Blackveil Forest, and Mornhavon the Black’s evil spirit imprisoned within it—she had nonetheless been tainted by his wild magic.Exhausted in body and spirit, Karigan had returned to her home in Corsa. But Karigan’s determination was no match for the Rider’s call. Ghostly hoofbeats echoed in the deep regions of her mind, and she returned to the court to find the Green Riders weakened and diminished. Rider magic was becoming unreliable, and she herself was having ghostly visions of Lil Ambriodhe, First Rider, and founder of the Green Rider corps. But why was she appearing to Karigan? And would Karigan be able to seek the help of a woman who had been dead for a thousand years?

On her long journey home from school after a fight which will surely lead to her expulsion, Karigan G’ladheon ponders her future as she trudges through the immense forest called Green Cloak. But her thoughts are interrupted by the clattering of hooves as a galloping horse bursts from the woods, the rider slumped over his mount’s neck, impaled by two black-shafted arrows. As the young man lies dying on the road, he tells Karigan that he is a Green Rider, one of the legendary messengers of the king, and that he bears a “life and death” message for King Zachary. He begs Karigan to carry his message, warning her not to read it, and when she reluctantly agrees, he makes her swear on his sword to complete his mission “for love of country.” As he bestows upon her the golden winged-horse brooch which is the symbol of his office, he whispers on his dying breath, “Beware the shadow man…”
Karigan’s promise changes her life forever. Pursued by unknown assassins, following a path only her horse seems to know, and accompanied by the silent specter of the original messenger, she herself becomes a legendary Green Rider. Caught up in a world of deadly danger and complex magic, compelled by forces she cannot understand, Karigan is hounded by dark beings bent on seeing that the message, and its reluctant carrier, never reach their destination.