In 3039, spiritual energy revived and the world changed. Birds, beasts, insects and reptiles mutated and evolved one after another. Human beings fell from the top of the food chain and huddled in ten safe cities. Demon Slayer City, the first of the top ten safe cities in the human race, bears the impact of massive demon tides every day. Li Ruoxi has a good-for-nothing brother who only knows how to drink and recite poems every day. He is drunk and dreams of death. Even the ten-year-old children in the city are more useful than him. She wanted to give up on this motivator countless times, until late that night, the S-class monster broke into the city, and when thousands of humans were in despair, a sword light spread across a hundred miles - the man smelling of alcohol came on the moon, with a sip of wine, a poem, and a sword to kill the monster. "It turns out... The mysterious swordsman who protects the entire Demon-Slaying City is actually my good-for-nothing brother?!"
