The main story is that Long Fei, a police officer of the Beijing Public Security Bureau, and his colleagues were ordered to go to Jiangnan District to carry out further new work. Take orders in times of crisis, not afraid of difficulties. Many years ago, Long Fei, who was still an underground party, and his lover had contributed to the revolution together, but because of the different progress of the work, the two began to separate early. In the course of his work, Long Fei discovered that the arrested martyr, Cheese, was inextricably linked to his lover, so with the close cooperation of his colleagues, he found the witnesses of the year and learned some very important evidence from them. They started to conduct a careful investigation and found that their lover was also involved. Like the tip of the iceberg, it is difficult to dig out..