"All Purpose Cultural Cat Girl Nuku Nuku" centers around the misadventures of Nuku Nuku, a highly advanced android created by the brilliant but eccentric scientist Dr. Natsume. Nuku Nuku is designed with the brain of a cat and the body of a human, granting her superhuman abilities, including enhanced strength, agility, and reflexes. Her creation stems from Dr. Natsume's desire to protect his son, Ryunosuke, from the chaos caused by Ryunosuke's estranged mother, Kyoko. Kyoko, the CEO of Mishima Heavy Industries, is determined to reclaim Nuku Nuku, whom she views as corporate property, leading to frequent confrontations.

The series blends action, comedy, and slice-of-life elements as Nuku Nuku integrates into Ryunosuke's daily life. Despite her combat-ready design, Nuku Nuku often struggles to adapt to human social norms, resulting in humorous situations. Her childlike curiosity and naivety contrast with her immense power, creating a dynamic character who is both endearing and unpredictable. Ryunosuke, a typical middle school student, finds himself caught between his father's eccentricities, his mother's relentless pursuit of Nuku Nuku, and the android's antics, which frequently disrupt his attempts at a normal life.

The plot unfolds through episodic adventures, with Nuku Nuku facing off against various adversaries, including Mishima Heavy Industries' agents and other experimental creations. These encounters often escalate into chaotic battles, showcasing Nuku Nuku's combat prowess while maintaining a lighthearted tone. The series also explores themes of family, identity, and the ethical implications of artificial intelligence, albeit in a comedic and exaggerated manner.

Key characters include Dr. Natsume, whose absent-minded genius drives much of the series' conflict; Kyoko, whose ruthless ambition and maternal instincts create a complex antagonist; and Ryunosuke, who serves as the emotional anchor, balancing the absurdity of the situations with his grounded perspective. Nuku Nuku herself is the heart of the story, embodying both the innocence of a child and the power of advanced technology, making her a unique and memorable protagonist. The series' blend of action, humor, and heartfelt moments ensures a lively and engaging narrative.