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. As a pitched battle rages around them, Toshiro and Ivy find themselves in a field of flowers that breathe the feelings and memories of every living thing. In this mysterious place, what strange new understandings will take root between Toshiro and Ivy?