A passenger on the train claimed to have witnessed a murder in a building. The police rushed to the scene and found that the vice president of the court had been murdered. A few days later, a flight attendant disappeared, and a murder occurred in the next city. The police discovered that these three people had appeared in a criminal case eight years ago. The murderer was obviously a revenge killing. However, the police did not know that the murderer was also eyeing the next key figure.
Concept: character, reasoning, humanistic care