Forgotten is a 2017 South Korean psychological thriller film written and directed by Jang Hang-jun. The film stars Kang Ha-neul and Kim Mu-yeol, with Moon Sung-keun and Na Young-hee in supporting roles.

Plot

Jin-seok, a young man, moves to a new house with his mother, father, and older brother Yoo-seok. Things seem off to Jin-seok in their new home. One rainy night he witnesses Yoo-seok being kidnapped and dragged into a car. Nineteen days pass and suddenly, Yoo-seok returns. Jin starts noticing discrepancies in his family's personality. He then realizes that they are not his family at all, but people pretending to be his family. He escapes the house and goes to the police. When he tells them he is 21 years old, the skeptical officer asks him what year it is. He replies that it's 1997; the officer reveals that it is actually 2017. Jin is, in fact, 41 years old.