The battle between Kin and Transitioners escalates when Addie, Evangeline's younger sister with magical Emrys in her veins, unwittingly starts aiding the Kin, happy just for the chance to finally use her magic, not knowing that breaking the Eighth Day spell could cause chaos in the world. Jax, Evangeline's liege, comes up with a plan to save Addie and show her the truth about the Kin--but it may be too late. It may be Jax and Evangeline have to chose between rescuing Addie and saving the world.