Jitaku Keibiin (2019)  

자택 경비원(2019), 自宅警備員 (2019), Homeguard

The individual you're referring to is a private security officer who has 20 years of military experience and specializes in technology and intelligence gathering. He pays close attention to minute details when it comes to the homes he is assigned to protect. His new mission comes from his father, Takao Kareki, and involves safeguarding his lover, who may become his future spouse. To ensure her safety, only the highest level of professionalism is required. Despite this, however, he observes everything in her home.