Song Zhiyi, a legendary figure in the city bureau's serious crime unit, suffered a head injury while hunting down a serial killer five years ago and suffered from anterograde amnesia - when he wakes up every day, all his memories of the previous day are cleared. She relied on an encrypted handbook and an electronic chip under her skin to rebuild herself, and spent twenty minutes every morning "re-recognizing herself."
Jiang Yan, an undertaker at a funeral home, is on the autism spectrum. He can sense sensory fragments from the last seven seconds of touching the deceased's body - temperature, touch, direction. He painted these fragments and never let anyone into his studio.
A bizarre drowning case forced the two to join forces - the deceased drowned in his living room, the doors and windows were locked, and the water in his lungs came from a river that dried up three years ago. The seven deceased had different causes of death. The only thing they had in common was that they all received a letter from "himself" seven days before their death.
As the investigation deepens, an illegal memory deletion experiment that has been dormant for twenty years gradually comes to light - fear is encoded into a death scene and implanted into the brains of young children. Those with the shallowest memories are the first to be triggered, and those with the deepest memories are the last to unblock it. Song Zhiyi himself was one of the experimental subjects that year.
Purpose: Face the darkness of human nature with the original intention of criminal investigation, and find the deleted truth while chasing the murderer against time.