Tells about an accidental death in a remote village in the northwest, which involves a series of sudden murders and "suspects": village doctor Liu Xinshen, psychology student Liu Yun, and Liu Xinshen's wife Kang Xiaoyan, Chen Quan, who was accidentally killed in the countryside, and the villagers who had a grudge with Chen Quan, etc., who is the unsolved murderer? What choice will the protagonist and village doctor Liu Xinshen make after experiencing two moral tortures in his life? The film focuses on the conscience and selfish desires of human nature, and explores the meaning and value of life.