Lin Shen is dead. When he woke up, he found that he had become the "trigger" of a killing machine - in each cycle, he must identify the murderer from among the three suspects, otherwise an innocent life will die for him in reality. What's even weirder is that every time he identifies it, the truth will be unlocked in his mind in the form of "replay". He began to realize that he was not solving the case, but was being used by others - the murderer was destroying the evidence perfectly through his identification.
When the sixth cycle begins, Lin Shen no longer faces a stranger, but his sister who has been missing for three years.
