It was serialized in Weekly Manga Action for only three issues in 1991, with the three published stories later compiled in a single volume collection in December 1997.

The story begins when genius inventor Kyūsaku Natsume transplants the brain of a cat found by his son Ryūnosuke on Christmas Eve, into a schoolgirl android that he created and subsequently stole from his former employer, Mishima Heavy Industries (owned by his estranged wife and Ryūnosuke's mother, Akiko Natsume).

An English language version of the OVA was released by Crusader Video in the United Kingdom on VHS featuring regional accents.

Then taking the cat, he gets in a car with his father, fleeing his mother's deadly aerial onslaught.

For that she first gets the friend Yoshimi hypnotized and brainwashed in sleep time to make her go on aboard Akiko's ship.

Nuku Nuku, this time can't perform as earlier because of her lack of swimming gear, which Kyūsaku shortly after provides, and with that she reaches the boat, defeats the episodic bot and in the ensuing chaos Akiko decides to not take her son, just for this time.

After a neighbor's kid with a heart of gold is dropped off to Ryūnosuke's house for temporary babysitting she decides to make the breakfast and lunch in Akiko's absence but ends up wasting everything.

Then the family with the kid go to a fresh produce market where another demonstration of the so called "evil" Mishima Industries takes place, resulting in another failed project running berserk among the people present there, which Nuku Nuku neutralizes in the usual fashion.

Later it's revealed that she participated in the event to earn the huge prize money for her father's underfunded research projects.

In a beach visit, Kyūsaku somehow got ''captured'' and ''taken'' to an underwater base, supposedly belonging to Mishima Industries, which is, in actuality, a hotel to boost the company's tourism revenue and prospects.

While doing this, Akiko's underlings Arisa and Kyōko try capturing her out of suspicion that Chie being a corporate spy.

After Ryūnosuke ingests a sip of the so-called ''DNA changer'' because of a mix-up, he turns into an alligator.

Nuku Nuku started out as just a stray cat Ryūnosuke stumbled upon taking a leak while on the run with his father Kyūsaku after retrieving (stealing) a prototype android of Kyūsaku's own design to keep it from being sold off to the military by Ryū's mother Akiko.

Nearly indestructible, she acts as Ryū's, and her own, bodyguard keeping from being reclaimed by the near dementedly overprotective Akiko.

In spite of her situations, she harbors no ill will towards Akiko or just about anyone, but is more than willing to resort to violence when push comes to shove.

Ryūnosuke Natsume Voiced by: Kazue Ikura (Japanese), Kira Vincent-Davis (English) The son of a brilliant if absent minded scientist and the over protective CEO of Japan's number one weapon's manufacturer, Ryū manages to take it all in stride and enjoys the times where he's able to squeeze in a normal life and quality time with either of his parents.

Kyūsaku Natsume Voiced by: Akira Kamiya (Japanese), Andrew Klimko (English) The brilliant, if quite eccentric, scientist who created a prototype android with funding from his wife's company.

He and his wife are not technically divorced and will still chat and bicker like any married couple when the chance arises.

Akiko Natsume Voiced by: Saeko Shimazu (Japanese), Kelly Manison (English) CEO of Japan's biggest military contractor, and an obsessively protective mother, Akiko's greatest goals are to reclaim Ryūnosuke from her husband and to capture Nuku Nuku in order to reverse engineer her.

Built in the image of a girl around Ryū's age, Eimi's activation resulted in an explosion that killed her grandfather, leaving her legally the property of Akiko's company.

(Eimi's own body doomed to detonate if pushed beyond its limit due a faulty or perhaps non-existent cooling system.)

A drama queen and an irrepressible hot-head, Eimi is able to think ahead and be clever but often lets her own impatience get the better of her.

Arisa Sono and Kyōko Ariyoshi Arisa voiced by: Aya Hisakawa (Japanese), Kaytha Coker (English) Kyōko voiced by: Akiko Hiramatsu (Japanese), Tiffany Grant (English) Akiko's two loyal henchwomen, they spearhead the attacks on Nuku Nuku and frequently suffer the consequences.

spin-off for a single-disc SDBD release on August 28, 2018, which includes Crusader Video's dub of the OVA as an added bonus.