Five Is Too Many(2005)

Original title: 다섯은 너무 많아

Dong-kyu has a truly curious job: collecting proof to denounce the free distribution of plastic bags. In a take-away restaurant he is caught off-guard by Sinae, an employee who runs after him and hits him on the head. Dong-kyu comes to and pretends he's amnesic. Si-nae takes him to her home, marking the beginning of a strange company of five.