Librarian Pei Ning, in order to protect rare ancient books and strictly guard the thirty-five decibel quiet baseline, is repeatedly complained about by readers as a cold 'decibel tyrant' for stopping readers' clicking pens, tapping keys, and shaking legs and other anxious noises. Facing the crisis of the ancient book room being about to be abolished and remodeled due to rock-bottom evaluation, Pei Ning makes a military pledge to double foot traffic, reach decibel standards, and clear complaints within one week. Facing the heavy pressure and resistance from the exam-preparing youth, whether he can use unique quiet ingenuity to resolve the conflict and successfully save this peaceful sanctuary remains unknown.