This is a story about how forgotten truths are re-seen. Chen Mu, a criminal policeman who had been chasing fugitives in the city for eight years, traveled back to the Liang Dynasty after his death and possessed the body of a small official from the Demon Suppression Department who was about to die. He discovered that monster cases in this world were all solved by monks' intuition, divination, and even the monster's surrender - no one investigated the scene, no one examined the traces, and no one asked "Why did the monster kill here?" What he has to do is to pick up the stupid methods of modern criminal investigation again: evidence collection, comparison, and logical deduction in this world where everyone believes in heaven, cause and effect, and fate. But the more he investigated, the more he discovered that behind the cases that were attributed to "demon disasters" lay an old score that the dynasty had not dared to overturn for three hundred years. The tone of this book is cold - not gloomy, but the kind of biting sobriety that comes from opening the window in the winter morning and letting out the white breath. The case is cold, the people's hearts are hot, and the truth is still smoking after seeing blood.