Rainy Day Serenade

On rainy days, Hina Katagiri always dreams about her younger self playing with a mysterious boy, but she assumes these thoughts are nothing more than a childhood fantasy. Now a high school student, she focuses on her club activities and protecting her great-grandmother's necklace. While at school, Hina is inexplicably transported to the backyard of a mansion, where she is greeted by one of its inhabitants, Takaaki Hongou. He mistakes the girl for his fiancée, Hinako Kitamine, but Hina, believin...