The story takes place in a modern city. A "Key Mystery Investigation Team" headed by private detective Shen Xiao has been involved in many strange cases: from bizarre secret room murders to confusing identity mysteries; each mystery seems to be related to a mysterious ancient key. As clues are uncovered one by one, the dark forces behind the case gradually emerge. The team members grow up through mutual hostility and cooperation. Behind the "failure and humorous" reasoning farce, there is a shocking conspiracy hidden. In the end, they not only solved all the mysteries, but also completed their self-growth and re-understanding of the world. The book has a tight rhythm, and contains life philosophy in its witty humor. It strives to make people laugh and want to put it down.
