The story revolves around "Minimum" or "minor miracle"— special hereditary powers discovered only in an extremely limited number of humans. Those who possess such powers are known as "Minimum Holders."
Partners Nice and Murasaki form a detective agency called "Hamatora" in Yokohama in 2014 — but their "office" is a table at Cafe Nowhere where they and their friends wait for clients. An old acquaintance of theirs, a cop named Art, hires them for a serial murder case he is investigating, and they discover that the murder victims are all "Minimum Holders." As Minimum Holders themselves, Nice and Murasaki are drawn into this case, whether they like it or not.