In the dark night, evil spirits infested the capital, and several royal family members and ministers died strangely one after another. Immediately, Longyan was furious, and the whole country was boiling. Yan Li, a young patrol officer on the imperial front, was ordered in danger. He issued a military order to solve the outstanding case within three days, and vowed to defend the dignity of the "night patrol" to the death. Faced with the ever-increasing pressure of the situation, the constraints of the secret service agencies, and the layers of traps of the criminals behind the scenes, Yan Li struggled to fight with the people and demons. With the approach of the truth, a fierce battle between monsters about life and honor, conspiracy and love, and the world and the common people also slowly kicked off.