Hortensia

Year 2079,
A world wide apocalyptic terrorist group created a super virus to destroy all of humanity.
Fortunately and unfortunately, rather than immediately affecting humans, the virus rotted away a vast majority of vegetation from the face of the earth. The exponential drop in oxygen caused serious panic throughout the whole world resulting in communities committing mass suicide and the spread of chaos.

Vincent Chesterfield is one of the leading scientists in the world trying to find a cure for the apocalyptic virus and restore vegetation once more.
There is only so much a human can do. All hope seems to be lost. That is, until Vincent makes a breakthrough discovery at a secret utopian garden.

(Heads up, I don't know shit about science, molecules, chemistry, etc... I'm just entertaining myself and hope you enjoy it anyways)