When perfectionist chaebol heir Yoon Yi-jun becomes the prime suspect in a mysterious murder case, his life turns chaotic. To investigate him from the inside, Kang Jae-hee, a skilled detective and former special forces operative, disguises herself as a male personal secretary to enter his inner circle. As Jae-hee navigates her dual life and Yi-jun’s demanding personality, the lines between professional duty, unexpected romance, and a high-stakes criminal investigation begin to blur in this thrilling workplace romantic comedy.