Stuntman Cha Dal-geon gets involved in a tragic airplane crash and ends up discovering a national corruption scandal in the process. Go Hae-ri, the oldest daughter of a deceased marine, decides to work for the National Intelligence Service as a secret ops agent in order to support her mom and younger siblings, although all she wanted to do is to become a civil servant.

After long and grueling hours immersed in brutal crime investigations, lead detective Choi Young Jin must face the particular horrors of singlehandedly raising her daughter Ha Eun. Any way you look at it, Young Jin’s got her work cut out for her, but it’s only a matter of time before her professional and personal worlds collide in new and disastrous ways.