Traditional martial arts.
Tian Er was mistaken for a murderer and became embroiled in a feud. After layers of investigations, the suspect was finally locked on the people around him, and it was finally proven that Tian Er was framed by an acquaintance.
The murderer also explained the reasons for framing Tian Er, all of which were caused by small grudges that led to catastrophe.
It's a good book worth reading, don't miss it!