Newly-instated detective Ishida Tomohiro returns home one day to find a naked man in his house. He asks Tomohiro to identify himself, only to vanish into thin air before the startled young man can come up with a response. Soon afterwards, Tomohiro becomes tangled up in an odd situation involving a killer sword that can possess people. Then the same guy shows up again: this time fully clothed and actually physically present. "Kyousuke" is a member of the supernatural task force affiliated with the police, and Tomohiro ends up being transferred there. Now he'll have to handle all sorts of bizarre and out-of-this-world situations alongside his extremely quirky new colleagues!

Source: Baka-Updates

This is an adaptation of the first instalment of Kouzuki Hinowa's two-volume light novel series, Keishichou Seikatsu Anzenbu Yuugeki Sousahan.

Tetsushi (a 5th grader delinquent who rules over the students of Jouin elementary), Ryuuchin (Tetsushi's right hand man) and Tsuda (their sometimes-ally), are known to everyone in town as the "three evil prankster kings."
In a creepy pharmacy located out-of-town, the boys meet an old man who bestows a strange and other-worldly power upon them. Soon after, our 3 young pranksters find themselves battling a variety of ghosts and demons...!?
(Source: M-U)