Natsu 's sister

What if Natsu wasn't the only child, what if he had a sister of whom he didn't know of?
One day as laxus and his team were of to a mission, finds a girl with pink color hair, hurt on the ground so they decide to take her back to the guild, where some mysterious events takes place and they come to know that Natsu, the girl with pink hair and zeref had a connection and now it is up to Natsu to solve the mystery of his life.