|“|| It's not a virus... IT'S EVOLUTION.
Kiyomi Nagashima (Riona Hazuki), the wife of Toshiaki Nagashima (Hiroshi Mikami), is left brain dead after a traffic accident on the day of their first wedding anniversary. Nagashima attempts to make her live again and steals her liver from her corpse. While examining the organ, something from it attacks his assistant Sachiko Asakura (Tomoko Nakajima) and turns the assistant into Toshiaki's dead wife. Nagashima later realizes that his dead wife is actually an organization of sentient mitochondria bent on making a new species that will wipe out humanity.
Toshiaki Nagashima is a researcher studying mitochondria. Toshiaki's wife, Kiyomi Nagashima, embodies Mitochondria Eve's consciousness and manipulates certain events so that Kiyomi will be killed. Toshiaki would then use his research to resurrect her, and her organs, through a donation, will be implanted in a girl that is meant to be the host of an Ultimate Being. Eve has been working toward these ideal conditions that entire billion or so years. Kiyomi gets her head crushed in a car accident.
A doctor, Takashi Yoshizumi, makes a deal with Toshiaki that he will give Toshiaki Kiyomi's liver in exchange for transplanting her kidneys to a girl named Mariko Anzai, and Toshiaki's uses the liver cells (which is convenient because he had been studying liver tissue regeneration) to attempt to recreate Kiyomi's body somehow.
The liver cultures manifest a gelatinous-looking creature that is able to morph into Kiyomi's visage. Even though Eve is structuring the egg of the ultimate being within Mariko, Eve needs the sperm of Toshiaki to fertilize it. She then proceeds to seduce the depressed Toshiaki into "giving her a billion years worth of love" Eve reveals that Kiyomi never really loved Toshiaki, but it was Eve that wanted him as a piece in her scheme. Eve forced Kiyomi to come to him and attract him in the right way while adjusting her personality as she felt it was necessary to further deepen Toshiaki's love. Eve continually explains that she has been waiting forever for these circumstances to arise. Much of this was suspected by the real Kiyomi through notes she would write herself which Toshiaki stumbles upon.
Eve then controls Toshiaki's student, Sachiko Asakura, at a press conference to announce that her plans are about to come to fruition. She then demonstrates her ability to activate the mitochondria within a human's cells to force them to combust. Toshiaki and Yoshizumi realize that this ultimate being will soon be born in Mariko now that Eve has Toshiaki's sperm.
They attempt to intercept Mariko but they arrive only to discover Eve has already set the final stage of her plan into motion. Eve ignites more people on fire as she moves to flee the hospital Mariko had been recovering at. Yoshizumi tries to slow her down through the hospital's security system, but Eve makes her way to the roof.
Toshiaki makes a final plea to Kiyomi's sensibility that he believes still resides within Eve. Eve continues to gloat more about how hard it was to accomplish everything and how humanity is finished. Toshiaki reveals he had fallen in love at first sight with Kiyomi long before they met by Eve's hand. Either through Kiyomi or due to Eve's disbelief, she refuses to accept this and inquires more. Toshiaki believes he has touched a chord with Kiyomi and slowly moves to embrace Eve, but she begins lighting parts of his body on fire that don't seem to burn him. As he finally touches Eve, it either reawakens Kiyomi and she did really love Toshiaki or Eve did love Toshiaki. As the two kiss they both light on fire and burn away as Mariko revives. The ultimate being is assumed to be dead as well.
The final shot shows when Toshiaki first saw Kiyomi and how entranced he was by her as well as showing that Kiyomi did take notice of Toshiaki further implying Kiyomi did have a will of her own since Eve did not recall it.
- Toshiaki Nagashima - Hiroshi Mikami
- Kiyomi Nagashima / Mitochondria Eve - Riona Hazuki
- Mariko Anzai - Ayako Omura
- Takashi Yoshizumi - Tetsuya Bessho
- Sachiko Asakura - Tomoko Nakajima