Shin Cha Il begins work as the leader of the audit team at JU Construction, where corruption runs rampant. Shin Cha Il doesn't have faith in other people. He has a cool demeanor and carries out his work with sharp judgment and decisive action. The audit team also includes rookie employee Gu Han Soo. He initially applied for the audit team as a stepping stone to get transferred to his company's Florida branch, but his plan was not easy because of Shin Cha Il. Unlike his boss, Gu Han Soo is a nice and warm-hearted person. Working with Shin Cha Il, Gu Han Soo grows as an audit team member.

Meanwhile, Hwang Dae Woong is the vice president of JU Construction, and he is the third son of the company's founder. His ambition is to become the president of the company by beating his two older brothers for the position.

Yoon Seo Jin is also a rookie employee on the audit team at JU Construction. She is an individualist who aims for success. She has a totally opposite personality from Goo Han Soo. She has also known Vice President Hwang Dae Woong since she was a child, but they pretend that they don’t know each other at work.