Mary Elizabeth Heart is a high school student by day and an intern at the Monarch City police department by night. Desperate to prove herself, Mary is thrilled to get the chance to work on a real case when the daughter of a powerful businessman goes missing.

However, what begins as a missing person's report soon escalates, leading to a girl with horns, a boyfriend with secrets and a monster in a poisonous lake. As the mystery starts to circle closer to home, Mary finds herself caught in the fight between those who once had magic, and those who will do anything to bring it back.