The Quest for the Missing Girl(1999)

Sousakusha

Shiga, a mountaineer, leaves his isolated lodge and returns to Tokyo in order to track down Megumi - the missing daughter of Tatsuko (Shiga's deceased best friend) and Yoriko (whom Shiga has secretly been in love with since before Tatsuko died). Shiga's investigation takes him into the world of "compensated dating" and disaffected teens and what he discovers there suggests that Megumi may have been abducted by a paedophile with a great deal of power and influence. In order to save the girl and regain the self-respect he lost when his best friend died, Shiga must break through the wall of silence and do what the police dare not.

(Source: Anime News Network) .