Prophecy Of The Stars [Fairytail Fanfic]

Lisanna has come back from the dead and everyone has forgotten about Lucy. She ignores this, putting up with her loneliness, thinking that their obsession with Lisanna was just a phase. But six months later, she decides to go after a stellar-spirit that she thinks could be a valuable addition to her key collection. What happens during the mission that convinces her to leave her nakama? And if she's not a Heartfilia, then who is she?