The Last Man (2018) on Netflix

Plot summary

The Black Month left the world in ruins within thirty days, and Kurt, a war veteran with PTSD, now lives in a storm-plagued city, sleeping beneath his bed with a weapon at hand. At a black market, a gang of neonazis rob and intimidate the traders. There Kurt meets Noe, a street prophet who preaches that an apocalyptic electrical storm is coming and gives him a book on survival. Hired by the security office run by Jessica's father, Kurt finds a basement door that is not on the blueprints and is told to leave it alone, and a child outside the office claims to know him. Convinced the warnings are true, Kurt starts turning his home into an underground shelter, and Jessica, who also believes, draws closer to him.