- TV Show: A Thousand Days' Promise (literal title)
- Revised romanization: Chunilui Yaksok
- Hangul: 천일의 약속
- Director: Jung Eul-Young
- Writer: Kim Soo-Hyun
- Network: SBS
- Episodes: 20
- Release Date: October 17, 2011 --
- Runtime: Mon & Tue 21:55
- Language: Korean
- Country: South Korea
Plot"A Thousand Days' Promise" tells the story of a woman losing her memory and a man who loves her unconditionally.
Lee Seo-Yeon (Soo-Ae) and Park Ji-Hyung (Kim Rae-Won) have known each other since they were teenagers. Lee Seo-Yeon lost her father when she was only 5-years-old and her mom left her when she was 6. Seo-Yeon was left behind with her younger brother Moon-Gwon. Her aunt took them in and raised in her home.
Seo-Yeon first met Ji-Hyung through Ji-Hyung's long time friend Jae-Min (Lee Sang-Woo), who is Seo Yeon's cousin. During this time Seo-Yeon and Ji-Hyung were just acquaintances.
Now as adults, Ji-Hyung is 32-years-old and his fiancee is Hyang-Ki (Jung Yoo-Mi). Their marriage is arranged by their parents. Seo-Yeon has moved out of her aunt's home and lives with her young brother Moon-Gwon. One year ago, Ji-Hyung and Seo-Yeon's relationship developed, even though Seo-Yeon knew Ji-Hyung was engaged. They promised to see each other until Ji-Hyung married. One year later, Ji-Hyung and Hyang-Ki's wedding date is set. Ji-Hyung and Se-Yeon say their goodbyes to each other.
On that night, Ji-Hyung tells his mother that he doesn't want to marry Hyang-Ki and he is in love with someone else. His mother tells him that he has come to far now and can't back out of the marriage.
Recently, Seo-Yeon starts forgetting simple things and has headaches. She feels strange, but believes it will pass over. Meanwhile, Seo-Yeon struggles with her breakup with Ji-Hyung. Ji-Hyung also suffers through the breakup, while dragged into preparation for his wedding.
Now, Seo-Yeon forgets pretty much everything and even important appointments. She blames her condition on her recent breakup, but her condition worsens and she goes to see her doctor.