In a distant future where the sun no longer shines, Toshiro Kamiya gives up his body to a sinister floral metamorphosis for a payday.

The earth of the distant future is covered in thick clouds, and the sun no longer shines. Plants wither, and oxygen is thin. To fight extinction, humankind has developed a technology that turns humans into plants, providing a small amount of oxygen. Is this process sustainable? Is it ethical? Toshiro Kamiya must consider these questions as he's faced with a difficult choice--save his family or save himself.

The mobile spiriflor Ivy's very existence spawns a fierce debate about the merits and dangers of transfloration, splitting the world in two. Having devoted their lives to Transflora Medical, Kamiya and Hourai strive to expose the ulterior motive behind the anti-transfloration protests, even as they question whether they are on the right side of the fight.