Senbei creates Arale and takes her on a test-run as a convincing little sister. However, she's not as tuned-up as her creator would have expected. / Arale is enrolled in school, and tries to win over the "tough kids" Akane, Taro, and his little brother Peasuke. Meanwhile, Senbei gets a crush on his creation's homeroom teacher, Midori Yamabuki.