Anni is the younger sister of the current emperor of Yeonghon, a country in which the royal lineage has been infused with spirit beasts known as 'Yeonghon Jimseung'.  After attempting to get through to her brother about his careless decisions as Emperor, Anni and her friend Choi Seunghyun - one of the military squad leaders - and his sister, Kanmi, make the decision to leave the capitol and live independently in the wilds.   An elite squad of warriors known as 'M21' escapes fr