Three witnesses, photographer Cheng Suqi, Oriental Research Society member Li Qiwen, and police chief Liang Ruijie, observed a councilor being shot. Suqi unwittingly took a photo, which was later destroyed. A committee member of the case's investigation, Prosecutor Jiang Zhushi, saw the photo at a film festival but did not see it again. After the Oriental Research Society faced arson, Qiwen discovered that it was an intelligence organization and was then chased. Suqi eventually found the photo, which revealed the witness and led to Qiwen's acquaintance with Zhushi and progress in the investigation. However, Zhushi persisted in investigating even after discovering the wide scope of the shooting case. Zhushi obtained a box of tapes with information about the case's motive and mastermind but was later killed.