Su Tang crosses into the zombie doomsday, is paralyzed, and symbiotes with the sharp-tongued cactus Citou. Relying on farming, the system mall, and plant abilities to survive, she discovers the truth about Shelter No. 03 and the Purifying Willow. When the endless night descends, she builds an oasis and becomes the merchant of light. Citou sacrifices himself to protect his master and turns back into a seed, but makes her awaken plant affinity. The truth reveals that Citou is a newborn of the plant civilization. Su Tang raises four newborns, forms a plant legion, and defends against the ultimate corpse tide. Finally discovering the source is the sky mutant cloud, she unites the whole territory to break it with a corn cob cannon and purifies the planet. The system activates the interstellar channel, and Su Tang enters the optical brain world to stand up again, leading Citou toward a new oasis.