Six years ago, a deadly virus contained in raindrops wiped out almost the entire population from the face of the Earth. An employee of the Appolo corporation, knowing about the impending catastrophe, managed to hide his children in a special bunker, ordered his daughter to protect his younger brother, and he himself went to save humanity. Six years later, the teenagers run out of food, so the sister decides to go to the surface for exploration and soon go in search of her father who never returned.