This is a very solid police procedural about a female-led investigative team that employs polygraph technology to solve crimes. Haunted by a 12-year old and very personal cold case, Ling Ran is a workaholic truth seeker who is after justice for both the victims and the survivors of violent crimes. This is a very driven character that fuses her own instincts and observations with signals from the lie detector to sniff out and drill down on suspects who lie like a dog.

The cases are based on real life cases that occur when common human fallings collide with social pressure and a spate of bad luck. They are quite simple with straightforward with often predictable solutions and some plot holes. But they are curiously addictive nonetheless and this is what sets this otherwise unexceptional police procedural apart. While at surface it looks like Lie to Me, it is actually a lot more like CBS's Cold Case, one of my all time favorite crime series. The stories are dark and sad and they feel very real. The magic of the narrative is that it brings the victims back to life - they have secrets, hopes, dreams, strengths, weaknesses; they all love and are loved. Regardless of how ordinary and humble their existence is, they are missed and their loss is a devastating blow to someone. All but the last case moved me to tears.
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The team dynamics are well written, well portrayed and enjoyable but overshadowed by the victims' and their survivors' haunting stories. I think Mo Xiaojie and his connection with the homeless orphan stole the show and gave this character the kind of growth and dimension that is missing in team leader and titular truth seeker Ling Ran's characterization.

Ling Ran is scarred by a 12 year old cold serial case that makes her the way she is but unfortunately this is not explored until the final case. As such, I find aspects of Ling Ran perplexing and never quite connected with her. This ends the drama on a final case that just doesn't resonate as hard as the earlier cases. I would prefer they opened with the final case and ended with the first case. This would have better established Ling Ran's backstory and made her more understandable and relatable. The first case is also one of the best cases and the one with the least dark ending that asks the question whether one ought to lie to protect the innocent, which would be a fitting note to end this drama on.

I only rate this a 7.0 because it really isn't the best, most intriguing and thrilling crime series out there. But it is quite well made and there is a lot of heart in the cases that will touch you in a lingering way so it is definitely worth watching.