Global Cataclysm: My Shelter Can Be Infinitely Upgraded

Blue Star has undergone drastic changes, and mankind around the world has been plunged into disasters one after another. Not only are they facing natural disasters, but they are also facing food and civil strife crises. Solar flares cause global high temperatures, ice ages, underground creatures influx, meteorites fall, irradiated wastelands, mutated ferocious beasts, and volcanic eruptions! Reborn half a month before the disaster, Ayaya obtained the system, built a simple shelter, and then upgraded it infinitely! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.