Kimi no Tonari de Seishunchuu

From Midnight Scans: Miu is living with her dad since her mom left them some years ago. While taking care of the house, Miu has missed the breaking news about thet new transfer student. When she meets Keita at school, he seems to know her quite well, but she doesn't recognize him at all. Who is Keita and why is he approaching Miu so openly?