"Zhao Shuxin (played by Liu Zifeng) is an engineer in a mining company. He is honest and hard-working. Playing chess is one of Zhao Shuxin's few hobbies. He cherishes his chess pieces very much. However, when he returned from a business trip, he found that he had lost one of his chess pieces. In desperation, he went to the post office in the rain and sent a "Black Cannon" letter. Lost 30..."