Nano Shinonome is a humanoid android created by eight-year-old professor Hakase. She lives alongside Hakase and their talking cat, Sakamoto, at the Shinonome Laboratory, managing household duties like cooking, cleaning, and grocery shopping. Though chronologically only about one to two years old, her physical form and cognitive abilities resemble those of an average teenage girl. Her design features black hair in a bob cut, black eyes, and a prominent key protruding from her back. Hakase insisted on this key for its perceived cuteness, while Nano initially saw it as an inconvenient marker of her artificial nature. Her attire varies: a bright red pullover with blue trousers for casual wear, a lavender T-shirt paired with a light-blue dress and wooden sandals for chores, or a tailor-made school uniform accommodating her back key. She wears green or pink pajamas for sleep. Nano's personality combines maternal caretaking with adolescent insecurities. She feels a strong sense of responsibility for Hakase, often acting parentally by restricting sweets and lecturing against mischief. Simultaneously, she deeply desires to be seen as an ordinary girl, causing anxiety about classmates discovering her robotic identity. Her naivety about societal norms sometimes leads her to misinterpret mundane situations as threats to her perceived normalcy. Her internal conflict drives her development. Initially, she conceals robotic traits through clumsy excuses or panic during unexpected limb detachment. Relationships formed at Tokisadame High School, particularly with friends Yuuko, Mio, and Mai, catalyze self-acceptance. A pivotal moment occurs when Yuuko affirms that "Nano is Nano," easing Nano's fears of rejection. By the series' end, she voluntarily keeps her back key, recognizing it as integral to her identity and signifying her embrace of both her artificial nature and human-like relationships. Hakase frequently installs hidden functionalities without Nano's consent, resulting in eclectic, often impractical abilities. These include dispensers for rollcakes (later fish cakes) in her left arm and sweet buns in her forehead, a USB drive within a removable big toe, a wristwatch display on her right arm, a forehead cuckoo clock, a head-mounted toaster, a soybean-firing machine gun, rocket-propelled hands, spontaneous limb detachment, super-strength, and flight via foot rockets. Nano remains largely unaware of these features and typically approaches tasks humanly, due to ignorance or her desire for normalcy. The key on her back serves minimal functional purpose, though manually turning it launches her big toe like a projectile.