Detective Story (探偵物語), Kichitaro Negishi, 1983

Naomi is a university student who is leaving for the US to study in a week; Shuichi is a washedup gumshoe whos hired by Naomis father to bodyguard his daughter until she leaves. Shuichi finds the job annoying and wants to quit. But he also has a screwedup ex and alimony to pay. Things go from bad to worse when Naomi and Shuichi stumble upon a murder that might involve the yakuza. They decide to find out who committed the murder but God knows what it will lead to.