My Dear Enemy (2008)

"Hee Soo (played by Jeon Do Yeon) is over thirty but still single. She has neither successful career nor love. She is a standard "loser". Just when she is about to fall to the bottom of her life, Hee Soo suddenly remembers that her Ex-boyfriend Byung-yun (played by Ho Jung-woo) once borrowed 3.5 million won from him and still..."