From MangaHelpers:

In this world, there are people known as "Minimum Holders" who are capable of specific "small miracles." A government funded elite academy trains these Minimum Holders in order for them to reach their maximum potential and serve national interests. Once, a student, of great potential named Nice, dropped out. He started a private investigator team with an assistant named Hajime and seemed content solving cases for his clients (which often involve Minimum Holders). A top student of the academy, Murasaki, has been tasked with bringing Nice back. Murasaki bristles at the claim that Nice has a higher potential than he does, but he ends up involved in Nice's detective activities... [tethysdust]

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"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 (Ryota Ohsaka) and Murasaki (Wataru Hatano) 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 (Hiroshi Kamiya), 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.
from ANN