What are the details of the Korean envoy case in Young Bao Qingtian?

This case is not new in the field of detective reasoning in terms of reasoning logic, but for the murderer Shen Liang, from his standpoint, he is the son of the Wolf Lord in Liao Dynasty, and he seems to be the boss. The two younger brothers behind him are either funny or weak scholars. Maybe they were young at that time, so they went to the Song Dynasty to do latent work. Shen Liang, with a cool head and high martial arts skills, is also very suitable for being a spy. I admire him very much. As a prince, he could have chosen to live a prosperous life and indulge in feasting every day like other princelings, but he didn't. It is very commendable that he chose to stand up for the country and the nation.