The "Mirror Prison" mental hospital, which had been abandoned for twenty years, suddenly reappeared in the world. The patients who had disappeared here died one after another in strange ways. At the scene of each person's death, there was an ancient mirror with no human figure in it. Lu Chen, a former crime scene reconstructionist whose license was revoked due to the "Red Moon Case" three years ago, accidentally received half of an old photo among the deceased's belongings - the person in the photo was his missing sister. In order to find the truth, he was forced to form a temporary investigation team with the hard-line detective Su Yan and the talented girl Lin Xia with "mirror memory" to delve into the fog of the Mirror Prison.
As the investigation progresses, they discover that the secret of transnational human experiments is hidden behind the Mirror Prison, and the core of the experiment is related to a "mirror Gu" that can control memory. Twenty years of time gap, tampered memories, teammates who are suspicious of each other, and the experiment leader lurking in the dark, involve the three people in a puzzle intertwined with blood and lies. Every ancient mirror is a container of memory fragments, and every time the truth comes closer, it is accompanied by more terrifying backlash. When the last secret of the Mirror Prison was revealed, they found that they had already become part of the experiment, and the real enemy might be around them.
