Erza is the sister of both Itachi Uchiha and Sasuke Uchiha. Better yet she's Sasuke's twin sister. When Erza Uchiha finally comes back to the Village Hidden in the Leaves and is told by the Hokage her entire story it's not hard for Erza to believe him.
The hardest part is: Sasuke doesn't. Sasuke believes that he never had a twin sister. That's because Erza was kidnapped right after she was born. She was taken to Earth but trained in the way of the shinobi by the one who kidnapped her and claimed to be her mother. How will Erza survive? Was her training enough? And can she convince Sasuke that she's his siter and stop him from making the biggest mistake of his life? Leaving the village and killing Itachi.
