Ginya Otonashi is a college dropout who works part-time for a pachislot publishing company while aspiring to become a novelist. One day, Ginya comes across a secret organization and gets pulled into a competition to become #1 in "Pachi Battle," which is all a part of the Slotseum, a pachislot competition.

Yasuda Ippei (Shonozaki Ken) is the son of Yasuda Seijiro (Osugi Ren), the head of Yasuda Group, Japan's biggest business conglomerate. Although he is the son of a distinguished family, he has absolutely no disagreeable areas and is liked by everyone. His academic achievements are exceptional. He completed his entire high school programme in 2 years and qualified for Tokyo University's Faculty of Law without studying for the exams. In order to establish his own concept of justice, Yasuda leaves his position as the heir to the Yasuda Group to attend the police academy. He becomes a detective at Kyobashi Police Precinct and bravely faces great evil.