Based on the character Rika-chan from Takara Tomy's long-running line of girls' toys, this is the third installment in the OVA series "Rika-chan" that aired in the 1990s. One Sunday. Rika goes to her friend Izumi's relative's house with Izumi and ends up answering the doorbell there. The house had a large tree in the backyard and was quite luxurious, but there was a shy girl named Akichan and her younger sister Tomochan who were a bit concerning.