Motel (1971)

Jeong-ok, jealous of her sister's love of Sang-il, exchanges her sister's blood sample with that of a leukemia patient during a visit to the hospital. Her sister, Jeong-ah, believing that she is going to die, runs away from home so as not to be a burden to her family or be subject to their pity. With her sister out of the way, Jeong-ok puts the moves on Sang-il.