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.

When Jeongin Bank faces bankruptcy, the Financial Services Commission aims to preempt Korea from another economic meltdown as it did in the 1997 financial crisis. With the Korean government having a substantial stake in the bank, things get serious. Chae Yi Hun is the chief of financial policy at the FSC. He hides the fact that renowned economist Chae Byung Hak is his father. Heo Jae is the chairman of the FSC and has ambitious intentions of fortifying the country's financial infrastructure. Lee Hye Joon is a girl who came from nothing. She works at the Ministry of Economy and Finance and wants to see the utopian economy with change. The money game begins now.