Professor Keiko Kurakake is contacted by her former mentor, the disgraced genius Dr. Haruhiko Yamagishi, who claims to have unlocked the secret to manual DNA evolution. Despite warnings about his dangerous history with human cloning, Keiko visits his secret lab, where she discovers that Yamagishi has successfully reversed his own aging and created mutated organisms. The encounter turns sinister when Yamagishi kidnaps Keiko to use her as the final subject in his twisted experiment to trigger a new "Cambrian Big Bang."
Keiko is torn between her feelings for Hideaki and the dark influence of Professor Yamagishi, who has infected her with a Cambrian DNA virus that amplifies primal instincts. As the virus triggers a volatile evolution of lust and aggression, Yamagishi manipulates both Keiko and Hideaki, pushing them toward their darkest desires. In the wake of this transformation, Keiko becomes an "evolved human," leaving Hideaki to question if he can still love the monster she has become.