City Hunter (1987) : 3x4

Ryo receives a strange request from Aiko, a female private investigator, to teach her how to fire a gun. At one point, Aiko gets horribly drunk after one cocktail, slugs Ryo and steals his gun, only to find it empty of bullets. The request gets even stranger when it is revealed that she needs a gun to protect herself from unknown thugs trying to prevent her from locating a strange dog for a six-year-old girl. Finally, Aiko's uncle appears in order to convince her to give up the private investigator business but when she refuses, he is hit by a car.