Ken Soma and Mai Hanasaki play the roles of superior and subordinate respectively in the bank, but their relationship is not harmonious.Soma Ken originally thought that by being transferred to the audit team of the head office, he would be able to get rid of the entanglement with Mai Hanasaki.

Three months later, Hanasaki Mai was also unexpectedly transferred to the audit class, causing the enemies to meet again.

As a newly arrived auditor, Mai Hanasaki's first task is to examine Nakajima, a senior teller at the Kayabacho branch.

Nakajima is known for his professional ability and high sense of responsibility in the bank, but such a seemingly impeccable teller made a seemingly simple mistake.

This mistake confused Mai Hanasaki. She didn't understand why Nakajima would make such a mistake.

As the investigation deepened, Huasaki Mai gradually discovered that things did not seem to be as simple as they seemed.

There may be deeper reasons and motives hidden behind Nakajima's mistakes.In the process, Soma Ken's attitude gradually changed.

He becomes interested in Mai Hanasaki's investigation and decides to secretly help her uncover the truth.