Arisa²: Arisa no Jijou

Morisaki Shinichiro recalls a childhood promise to a girl who was about to move away, but it feels like a recurring dream. After being woken by his sister, he heads to school and encounters a girl who trips and faints. He takes her to the nurse's office. Later, a new student bursts into class, yelling his name and resembling the girl he helped. The class leader subdues her, and Shinichiro brings her to the nurse as well. He discovers two girls with nearly identical appearances: Sawatari Arisa, the quiet one he rescued, and Sawatari Alyssa, the energetic one who knows him and wears cat-ears he remembers. That evening, he learns his uncle has taken both girls into their home.