One summer ten years ago, Song Kang died, which was a scandal.
The upright and kind-hearted deceased, the ambiguous location, and the humiliating death situation all make people's belief and pursuit of the so-called "heroes" collapse like a building.
Late that night, the entire Song family was massacred. Song Ji, who was only twelve years old, was locked in a closet by his mother, Yu Qiurong, and escaped.
Bullying and criticizing classmates at school, mother Yu Qiurong's collapse and curse during her lifetime, overwhelming reports, and the shrill screams outside the small door that night, the frightened girl only felt full of confusion and a beam of desperate moonlight.
"I don't know the truth, but I don't want to be trapped in that crack in the door all my life. I want to go and find it, even if I try my best."
The puzzle is complicated, murders occur one after another, vague love, the complexity of human nature, what she sees outside the crack of the door, and how she will choose...
Purpose: Expose the darkness and find the truth