The Emerald Cavern (Graham, Mitchell. Fifth Ring, Bk. 2.)

Book Description:

Destiny and tragedy placed an awesome power in the hands of young Mathew Lewin. But is he its master -- or its pawn?

Needing shelter from his enemies, Mathew Lewin has come to a kingdom neighboring the one he saved by harnessing the might of the ring. The haven he has chosen, however, is anything but safe. Treachery and mysterious murder plague this land and its giant king, threatening a devastating civil war and giving rise to dangerous suspicions aimed at the boy who seeks sanctuary. But Mat fears the destructive resources at his fingertips -- he must learn their secrets or be destroyed by them -- and his quest has led him here. Now, to find the answers he covets, he must confront another who wields the power . . . and venture into an enchanted place of darkness where the truest and most terrible of evils dwells.