Once, long ago on planet Earth, there lived humans. Along with the humans were mythical creatures. They were known as Beasts. Now an organization known as End plans to eliminate every Beast. Adena is one of many soldiers that go out to destroy the Beasts. Her already abnormal life gets turned upside when she is kidnapped by a hyperactive Beast and learns of a secret. Adena doesn't know who to trust anymore, and as the days go by, she wonders what is right and wrong. Should she believe the people she has been with her whole life or the ones who show her the joy of life?