Unbridled Magic. Elemental Magic, #4

Nita Young couldn't be happier: she's getting ready to marry her soul mate, Keenan Donovan, in the company of close friends and family. Everything is perfect.until a major earthquake crashes the party. As the only elementals in the area, Nita and her friends are sent to investigate a local volcano as the cause. Instead, they find an archaeology team has unearthed an ancient artifact buried deep in the mountain.
After Keenan touches the relic and gets jolted with magical energies, he starts developing some unsettling new powers. Messing with alchemist magic is dangerous, especially when shadow hounds emerge from the volcano seeking the artifact and those who took it. Nita and her friends must battle the dangerous creatures while trying to figure out where the archaeology team stashed the relic. To make matters worse, Keenan's new powers are growing unstable, and Nita has to find a way to reverse the artifact's spell before its consuming magic tears Keenan apart.