Tonagura!

Kazuki has been waiting 10 years for the day her neighbors will move back in to their old house. She has had a crush on their son, Yuuji, whom she considers as her first love but to whom she never managed to express her feelings for him before they moved out. Yuuji often came over to play with Kazuki, Kazuki's older sister, Hatsune, and Yuuji's sister, Marie, when they were kids. Her ideal depiction of Yuuji was soon shattered when he turned out more than she had expected. With their parents off in South America, both families must learn to live with each other and rekindle the childhood feelings they shared together.