The Daughter-in-law.

Jang-hyeon is in the leasing business and he lives with his son Byeong-cheol. One day he gets a call from his daughter-in-law in the States that she's coming to Korea for a while and will be staying at Jang-hyeon's house. Jang-hyeon goes to pick her up from the airport and Byeong-cheol calls his girlfriend for some mature fun, but the daughter-in-law walks in.