Glimpses of Light in the Dark River

What appears to be an ordinary kidnapping conceals a deeper conspiracy. When Lu Shen arrives at the scene and calmly replies, "No money. Kill her," he isn't truly indifferent. He's instantly spotted the flaw in the setup: the tiny tapping motion of his wife Su Wan's finger is their agreed-upon danger signal, and the tattoo on one kidnapper's neck is linked to an unsolved case from three years ago.