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.

Hourai has received orders from Dr. Kudai and is off to a Buddhist temple to find the researcher who transflorated Toshiro. But even there, strange things have been happening amidst the spiriflora. Can Hourai figure out why an important ritual has failed-and who might have wanted it to?