This is the story of Zelena Dragneel, the younger twin sister of Zeref Dragneel, and older sister of Natsu. After her parents and Natsu were killed by dragons, Zelena is accidently separated from her twin brother Zeref and ends up being found and taken in by the Nature Dragon Foresta who raised the young girl and even teaches her Nature Dragon Slayer Magic. One day Zelena had suddenly started to undergo Dragonization right around the same time Zeref first became cursed by Ankhseram which was what had led her to reuniting with her brother. Followed sometime later by Zeref finally bringing Natsu back to life and later leaving him with the Fire Dragon King Igneel, leading up to the Dragon Slayers being sent to the future.