Youthful Older Sister (2018)
Original title: 어린 누나
Youthful Older Sister is a 2018 Korean-language romance movie directed by Kim Tae-soo, with a running time of 1h 30m. It stars Seo Won, Min Do-yoon and Shin Joon-hyun.
A young man grows up with his older cousin who is like an older sister to him. When he grows up, he goes to visit her at her home where her friend is also visiting. The three of them under roof make for some interesting circumstances.