The Stonekeeper's Curse: A Graphic Novel (Amulet #2)

Emily and her brother Navin head for Kanalis, a beautiful and mysterious city of waterfalls, where they hope to find the antidote for the poison that felled their mother. That cure lies in the eggs of a giant serpent atop Demon's Head Mountain, but the kids' archenemy, Trellis, is headed for the peak, too. It's up to Em to triumph over evil while controlling the amulet's power - without losing herself!