The fantastical and magnificent city of Chang'an, a city woven with gears and mechanisms, is home to both humans and demons living side by side beneath its upturned eaves. Di Shao, a genius young man aspiring to become "Chang'an's Number One Detective," possesses exceptional crime-solving skills and a sharp tongue; while Asa, a rookie wolf demon constable, is formidable in martial arts yet kind-hearted. A bizarre murder case forces these two adversaries to team up, embarking on a hilarious and bickering detective journey. As clues point to the heart of the city, can this unreliable duo protect the joyful daily life of this fantastical city? And what earth-shattering secret lies hidden behind the bustling and prosperous Chang'an?