Diver Lin Lan accidentally comes into contact with a mysterious extraterrestrial life-form known as the Blue Membrane. Her wound heals within an hour, and her body begins to undergo strange mutations. Meanwhile, the hotel shuts off its water supply and seals the building as infected individuals quietly blend into the crowd. Unknown organisms are also continuously hatching in the underground pipes. Within 72 hours, the Blue Membrane evolves into a completely new form each time it adapts to an environment. No one knows whether they will be the next to be replaced.