The city one night, police brigade suddenly received alarm telephone, a small gun case. The duty of Liu and officer Meng Jinfu grew up site, found that is a dog. Seeing others are in favor of major, observing eager young officer Mengjin feel very grievance, but Liu to persuade Mengjin to detailed investigation of the case. Before starting, Liu 's son was in school injured in hospital, Liu had no time to see the children.