Takes place in Japan, at least 100 years in the future. For some unspecified reason, about 100 years before the start of the series thick dark clouds appeared in the sky and blocked out the sun, casting the world in a permanent cold night. This caused all the natural plantlife to die out and has made oxygen increasingly scarce. To combat this, humanity has invented something called "transfloration", a technology to grow plants from humans. A seed is inplanted into a dying person, and the plant uses the lifeforce of the person to grow to maturity over the course of two years, ultimately turning the human into a special plant that can produce oxygen under weak light. For ethical reasons the procedure is only available to people who are already dying, but the government pays 10 million yen in financial support to anyone who has undergone the surgery. You can imagine how that works out in a world already going to shit.
The story follows two childhood friends who meet again after having grown apart, one of them fallen on hard times and the other working at the transfloration institute, and examines the consequences of this new technology on the people, politics and society from the perspective of these two characters.
I just saw that the first volume is available on Viz, so please check it out if you it's accessible to you and anyone else reading this. There's a real rawness to the way it depicts this whole premise, the art is gnarly with some great character designs and body horror, and the characters are all interesting and relatable to varying degrees, not to mention a story of mystery and intrigue on top of it all.
