Yoimonogatari 

Araragi Koyomi's university arc (Monster Season) Oddities x Mystery "Do you still feel like playing detective?" From his kouhai at Naoetsu Highschool, Higasa Hoshiame, comes rumours of the kidnapping of an elementary school girl. Araragi Koyomi, now a first-year university student, along with Hachikuji Mayoi, Oshino Shinobu and Ononoki Yotsugi begin investigating, but...! This modern day oddity! Oddity! Oddity! In the Evening darkness, youth shines brightly. (Source: Kodansha, translated)