Mio and Yüko attempt to prove that Nano is a robot only to fail, but Mai manages to film evidence. Nano tries to convince the Professor to remove the wind-up key on her back as it's hindering her school life, but gets mad and shoots the Professor with a pellet gun every time a dubious item comes out of her body. Ms. Nakamura plans to kidnap Nano, as she is interested about her robotic nature...