Observing My Mom's Friend's Son

Se-i Lim spends time with her mother, Hyejeong, at Taeseung Mall, where they meet Myeonghyeon, the mall’s CEO. Myeonghyeon asks Se-i to tutor her son, Seunghyo. However, Se-i accidentally walks in on Seungju, Seunghyo’s older brother, naked. Seungju accuses Se-i of being a pervert, but Myeonghyeon doesn’t believe him. Seungju insists Se-i is the only one who has seen him naked, and Myeonghyeon, confused, wonders if Seungju might be gay. Concerned, Myeonghyeon asks Se-i to investigate Seungju for three months. Will Se-i uncover the truth?