Sweet Shadows (Medusa Girls #2)

Teen triplets Gretchen, Grace, and Greer, descendants of Medusa, continue to battle the monsters who walk the streets of San Francisco, unseen by humans, but realize they must enter the abyss if they are to protect their loved ones--and their world. Warring factions among the gods of Olympus are coming; creatures of the Abyss are pushing into San Francisco; boys in their lives hide dangerous secrets.