Jae-ho, who inherited his late father's elite company, hires Hyeon-jeong to help his younger brother Sang-ho, who has been retaking the college entrance exam for nine times, on his studies. However, during the study sessions, Sang-ho is only filled with thoughts of having sex with his private tutor. Meanwhile, Jae-ho, who has secretly loved Hyeon-jeong for a long time, confesses his feelings to her, and the two officially become lovers. But one day, Hyeon-jeong is betrayed by her friend Na-hee, whom she brought in to help tutor Sang-ho in English.

Min-hyeok and Hae-ji, Seon-woong and Mi-mi, who came on a couple's trip to Vietnam, are very excited. Min-hyeok also enjoys a thrilling secret meeting with his wife Hae-ji as well as Mi-mi, who has been in a long-term relationship, and has a satisfying time. However, Min-hyeok suddenly feels intense pain and stops breathing, and when he opens his eyes thinking he is going to die, it is his first day in Vietnam. Min-hyeok, who is confused about everything, finds out that there is a reason for the vacation that ends in death...