A cat's brain in an android girl's body means the show operates on pure cartoon logic where the rules change every five minutes. Nuku Nuku treats ultraviolence and earnest family drama with the same deadpan commitment, which makes the whiplash genuinely funny. You're watching a 1992 OVA that swings between protecting a kid from his homicidal ex-wife and a cat doing cat things in a giant robot body, and it commits to both with zero irony.

Ryunosuke's beloved cat dies in an accident, but his inventor father has an unconventional solution: he places the cat's brain inside an android body built in the shape of a young girl. Nuku Nuku becomes part sister to Ryunosuke and part bodyguard for his father, with enormous strength and catlike agility. She needs every bit of that power, because Ryunosuke's mother has other plans for the family. Divorced from her ex-husband, she keeps trying to kidnap both him and their son. Her reasons for wanting the boy are plain motherly love, but she wants her genius ex-husband to design weapons of mass destruction for her weapons company. Nuku Nuku tries to live as an ordinary high school student while adopting the role of Ryunosuke's older sister, yet she usually ends up protecting her family from the explosive clashes between his parents. The result is a comic sci-fi action romp with mecha elements, built around a cat-brained android girl who will do whatever it takes to keep the people she loves safe.