Aidan O'Linn's childhood ended the night he saw a demon kill his mother and mark his sister, Ava, with Darkness. Since then, every three years the demons have returned to try to claim her. Living in the gritty, forgotten corners of Los Angeles, Aidan has managed to protect his sister, but he knows that even his powers to fight demons and speak dead languages won't keep her safe for much longer. In desperation, Aidan seeks out the help of Sid, the...