Hitozuma uwaki chôsa: Shujindewa manzoku dekinai

人妻浮気調査 主人では満足できない (original title)

Synopsis

Private detective Amon receives a request from Mami. She asks him to investigate the infidelity of Tadafumi's wife, Keiko. Keiko secretly appears in adult videos and gives money to the gangster-like Mochizuki, who sleeps with her at a hotel...