"70°C Heatwave Hits: I Have Infinite Space & Nuclear Bunker!"

What the story is about

After being betrayed and killed during a catastrophic heatwave, Jang Yang is reborn six months before the apocalypse and awakens a jade pendant's powerful pocket-dimension abilities. He uses his foreknowledge and new powers to amass supplies, build an impregnable shelter, and prepare to survive the coming collapse while confronting those who exploited him in his previous life.