The Song of Crazy Love.

Yi-su, a 37 year-old professor, can't forget her first love Joon-ho who's missing in action in Vietnam. She meets Hyun-woo one day, who look surprising like Joon-ho. Hyun-woo investigates Yi-su who lives in the past and discovers that her pain stems from the Vietnam war. Hyun-woo can't help falling in love with her even though he's a student. On a trip to Busan, he confesses his love for her. But he soon realizes that the only man for her is Joon-ho. Min-cheol who fought along with Joon-ho sells his belongings to Yi-su at a high price. He tells her that Joon-ho died in a fire and they argue aggressively. Min-cheol commits suicide afterwards and Yi-su is also found dead in the campus pool.