Taekang Group's successor, Yoon Yi-jun, is the prime suspect of a shocking murder. To uncover the truth, Kang Jae-hee goes undercover as a male secretary to keep an eye on Yi-jun. The closer they get to what really happened, the closer Yi-jun and Jae-hee become. Will Jae-hee, who is hiding her identity, and Yi-jun, who is hiding a secret, be able to let their true feelings be known to one another?