Taekang Group's successor, Yoon Yi-jun, is suspected of murdering his secretary, but the group's power and lack of evidence impede the investigation. To find key evidence, special forces-turned-detective Kang Jae-hee applies to be his secretary, not as a woman but as a man! She manages to get the job, but Yi-jun doesn't let his guard down. Jae-hee risks getting exposed on her first day at work.