October 30, 2019
Yūko suggests throwing a surprise birthday party for Nano today which Mai and Mio agree which at the same time, the Professor has made a smaller wind-up key for Nano only for Sakamoto to accidentally crush it but the Professor promises to make a new one once she comes back from school. At school, the Principal is shocked to see his statue replaced by the Vice-Principal's own statue but his plot is exposed when the movers reveals they still have the Principal's statue and called the Vice-Principal's statue ugly. After Yūko avoid several accidents with her friends and unintentionally help others, she tells Nano that she, Mai and Mio will be coming to her home as the three are holding the surprise party there. Ms. Nakamura finally finds her pet cat Taisho, who is actually Sakamoto, who is horrified to see his old owner due to how bad she was in taking care of him and manages to escape after Ms. Nakamura meets Nano and tells her to find and return Taisho if she ever finds him. When Nano returns home, the Professor removes Nano's wind-up key, revealing anyone can pull out the key except Nano herself, as she finishes the smaller one. As Yūko, Mai and Mio arrives, Nano, after some thought, decides to keep the wind-up key after realizing that her friends still treat her the same no matter if she's a robot or a normal girl. As everyone celebrates Nano's birthday which coincidentally was today, Nano learns to her chagrin that the smaller wind-up key was actually an add-on that makes her wind-up key spin when she's happy. Despite that and having two ruined birthday cakes, everyone has a good time at the party.