Ten years ago, the "11.24 Serial Murder Case" caused detective Lin Xu to lose his mentor Chen Yan, and he himself became a decadent and marginalized person; ten years later, a new case with highly similar tactics broke out, and a copper button he obtained by chance actually allowed him to travel back in time and touch the secret details of the old case from the perspective of a bystander.
Zhou Yu, a rising star in the police force, was ordered to handle a new case. He was wary of Lin Xu's "time travel memories" at first, but after he repeatedly provided key clues, he gradually put aside his prejudices and formed a secret alliance with him. The two pursued the case on two fronts, piecing together the chain of evidence in reality while digging into the past through time travel. They discovered that behind the old and new cases, there was a shocking shady story about Li Wei, a senior police officer. In order to cover up the transaction scandal with the cult, he not only planned the murder that year, but also framed Chen Yan, causing him to become a vegetative state.
The cost of time travel made Lin Xu increasingly confused between reality and the past. However, in order to redress the injustice of his mentor and to let the victims rest in peace, he and Zhou Yu set up a trap to round up the real culprit. In the end, after ten years of unjust cases, Lin Xu regained his original intention as a criminal police officer and became a partner with Zhou Yu, proving that justice may be late, but it will never be absent.
