Seven Teeth

Thirteen-year-old Shen Sanqiang walked into the Beijing Overpass with an iron key and spent seven years learning the crafts of the twelve gates of the world (the four gates of deception and the eight gates of serious business). Each door has a master. After completing the training, the master will make a mark on the key. After leaving the army, he discovered that his father was not dead. The key opened not a door, but a road he had never thought of taking.