The story centers on Minemori Kotoha, a woman who has been offered work at Suma Research Company "Anti-Detective Section," and Sasaki Rena, its only investigator. This section focuses on rooting out corrupt detectives and removing them from their positions. 

While the two women spend their days investigating crooked cops, a new criminal is beginning to make his move...

From MangaHelpers:
Yuto works for a magazine company known as "Kadokawa". His current project revolves around a mysterious phenomenon occurring inside the city. Someone or something has been placing stickers of a sumo wrestler's face all around the city in various places. No one knows who is placing the stickers or what their objective may be, but these stickers have been showing up in places for a while now.
Yuto now needs the help of an appraiser to solve this mystery. Searching through the web, he finds an appraiser known as the "Appraiser Q". Her name is Rinda Riko, and she has the ability to appraise anything (or anyone) and solve any mystery thrown her way.