I'll just show the summary but I'd say that it's similar with the questions of who could have done it then and are they starting back up or did they never stop, or is it possible that they're copycat kills.

"Moo Yeom is a detective. 20 years ago, he was a Buddhist monk, but he got into trouble with a man named Gap Dong. To cut ties with him and cut off whatever karma would arise from his involvement with Gap Dong, Moo Yeom became a detective. After the statute of limitations expired, Gap Dong appears once again. Moo Yeom sets out to catch him once and for all."

A funny yet intelligent main character who seems to always find himself the talk of the town from the higherups, like Wei Wuxian does. The only difference is where Wei Wuxian receives scorn for his brilliance, this main character receives praise. While there is a female/ male romance, it's not the heart of the drama, the heart of the drama is about uncovering the truth, just like The Untamed. It also has Xiao Zhan in it toward the end! It has that serious yet comedic feel that The Untamed has, although the season does end on a bit of a cliffhanger...However, I believe that there's supposed to be two more seasons, so way more adventures, betrayal, hilarity, and the uncovering of the truth! Also, this drama is based on a huge book that involves time travel and since China doesn't like that, the drama writers also had to dance around the censorships, just like The Untamed! Give it a try!