A pandemic of a mysterious disease, completely harmless to humans but deadly to plants, begins rapidly destroying all flora in nature, causing a significant drop in the oxygen levels of Earth's atmosphere. According to scientists' calculations, if the current rate of oxygen depletion continues, humanity will face extinction within a year. The shortage of oxygen is already noticeable in the air, making oxygen masks and tanks skyrocket in price and turn into essential survival items.

Teams of botanists from around the world have identified the cause of the mysterious disease and are racing to develop a vaccine for plants, but it remains unclear whether they will finish it in time. Meanwhile, a retired amateur gardener seemingly stumbles upon a strain of lilac resistant to the disease…