Humans were always at the top of the food chain. That is, until 36 years ago when Tokyo was overrun by parasitic plants known as Jinka. No one knows why or how this happened, but the Jinka are out for blood. They multiply by spreading their pollen. Once infected, your fate is sealed—either turn into a Jinka or be burned alive. Only those with money can afford to be vaccinated against the pollen, but Kingo barely has enough to feed himself and protect his sister, Kayano...who is infected by an odd Jinka that doesn't attack others. But when she is reported and the Flower Funeral Force attempts to prune her, all hell breaks loose, and Kingo soon finds himself the host of a Jinka too...and that Jinka is Kayano. Now Kingo will stop at nothing to make her human again.