Hanasaki Mai is but an ordinary employee of a bank, with zero diplomacy. She doesn't think twice about pointing out her boss' mistakes. Her job is to investigate any wrongdoings in the bank branches. She is the voice of the suppressed staff who are unable to go against their bosses. Her partner is the veteran staff, Soma Ken, whose career with the bank had reached a dead end, no promotions in sight. Together, they resolve all the non-compliance issues at the bank.

Every day, bank branches encounter various problems like missing money, information leaks, loan problems & breach of duties. Hanasaki Mai's job is to go there and fix the problems. She is able to do so even though she is just a bank clerk without higher-level powers. Because of her character, Hanasaki Mai will not keep still when she sees a wrong. She's willing to stand up for the side of the weak, regardless of the relation between the top and bottom factions of the bank.