The Kamen Rider Amazon movie is a theatrical version of episode 16, Garander's Tokyo Sea of Flames Operation!!, depicting Gengoro Beastman's attempt to execute Garanda's Tokyo Sea of Flame plan.
The “Amazon Livestock Project,” a mysterious care facility, the Amazon extermination organization 4C (Competitive Creatures Control Center) pursuing Haruka Misuzawa . . . all come together in a tale of symbiosis and competition; the mortal combat between the carnivore and herbivore. And, finally, an end to the troubles and conflicts of the Riders, two beings confronting a fierce fate.
The series revolves around a race of genetically-engineered mutants known as Amazons, around four thousand of which are set loose into a city after a mysterious lab accident. Though normally able to mimic humans and live peaceful lives, the Amazons transform into ravenous flesh-eating monsters when the medicinal suppressant within their armlets runs out after two to three years.