In the year 2010, practically one hundred percent of Cat Earth's GDP comes from the megacorporation Catty & Co., which is rapidly spreading across the rest of the galaxy. Here lives Tamala, a beautiful yet foul-mouthed cat, who decides to travel to the planet of her birth, Orion. After an unfortunate crash landing on the planet Q, Tamala meets Michaelangelo, a fellow cat, whom Tamala refers to as "MoiMoi." As Tamala and Michaelangelo explore the planet's capital, Hate City—which is under martial law to separate the feuding cat and dog populations—they pass by graffiti and museum exhibits about the ancient cult of Minerva that speak of something dark and sinister. After Tamala catches the eye of the extremely violent motorcycle-riding Kentauros, she and Michaelangelo flee, but mysteries about Tamala's identity continue to surface. Why did Tamala originally leave Orion, and what exactly is her connection to Catty & Co.?

The film takes place on a certain isolated island, at a certain middle school, and on the eve of the culture festival. A boy quits baseball after playing his whole life and has a fight with his best friend. Then, they suddenly meet a mysterious, red-eyed girl named Noruda, and a huge typhoon hits the middle school.

The game is set in the continent of Babel, where the Tower of Babel looms large over seven nations. After the invention of alchemy led to its use as a tool of war that brought humanity to the brink of extinction, the seven nations struck an uneasy peace that led to a prohibition on alchemy for hundreds of years since. In the Continental Year 911, the nation of Lustrice broke the pact by assembling an army bolstered by alchemy, with ambitions of conquest over the continent. Led by Envylia, the six nations allied and struck down the rogue nation, casting alchemy once again to darkness. But 20 years after the war, alchemy once again begins to cause chaos in the land. 

(Source: ANN)

The plot of this OVA is a rough adaptation of the first four chapters of the Guyver manga. It covers the same basic elements of these chapters; Genesis of the guyver, Fight with Vamore, Fight with Guyver 2 and the introduction of Guyver 3. Main differences are the exclusion of Tetsuro and his replacement by Mizuki, The replacement of Lisker with a female Agent "Valcuria", and thus a female Guyver 2. There is also a look at Sho's psychology of how he deals with his situation including a very harsh moment where his friends are assassinated in cold blood. One night, high school student Sho Fukamachi discovers a mysterious metal object. Then in a blinding flash of light, Sho finds that he has accidentally fused with the Guyver, a mecha of mysterious alien design. Now, to save his girlfriend, Mizuki Segawa, along with the entire world, Sho must become the Guyver to fight the Chronos Corporation and their biocreatures, called Zoanoids, who are hell-bent on world domination.