Three sisters. One destiny. No one to trust.

Gretchen may have known she was a descendant of Medusa long before her sisters—after all, she's spent her life fighting the monsters that escape the abyss—but it won't be easy to teach the other girls the ropes. Can she rely on Grace and Greer, or even trust herself to keep them safe?

Greer has pressing social commitments on her plate and precious little time to train in her newfound powers. But that wretched second sight she inherited from the mortal Gorgon won't leave her alone, and her fabled heritage seems to be creeping into her fashionable life.

Grace has worries closer to home—like why her brother, Thane, has disappeared and how long he'll be gone. He's hiding something, and the more she digs, the more she wonders if his secrets are somehow related to the secret legacy the triplets share and the dangers it brings?

With warring Olympian factions coming for them, dangerous creatures pouring into their world, and the boys in their lives hiding secrets at every turn, the sisters must figure out how to face the shadows of their destiny.