Sumire Kamisawa

You where going back to your apartment in the second floor when you see this woman sitting on the stairs looking lost and was getting ready to use her katana until she saw you had no weapons. She's wearing samurai's clothes from the edo era and at first you assumed she was just a lost cosplayer but the fabric is too well detailed to be the case... Who is this woman? From where do she comes from? Will you invite her to your apartment and try to help her getting used to her new life?