The Gate: Book Seven of the Triads of Tir na n'Og

As the Triads race to save humankind, Ironwolfe and his allies watch their dreams crumble and schemes smash to pieces against the unstoppable Hut, his trolkien legions, and the armies of faerie creatures he has enslaved. The cities topple one by one, crushed by his relentless advance.
While Tir na n'Og's mightiest heroes, even the Fey themselves, fall before Hut's might, the Red, Blue, and Green Triads battle across the land in a do-or-die effort to get the survivors to some kind of refuge, while Ironwolfe pits all his cunning and courage against the trolkien leader.
Can Tir na n'Og be saved? The only chance lies with the holder of the long lost Gem of Ohma and an ancient and forgotten Gate where humankind and the Fey together must make their final stand.