12 Years Promise (2014)

Jang Guk is a country bumpkin who just transferred into a school in Seoul. She falls for Yoo Jun Su, the most popular boy in school. As her crush on him grows, they spent the night together which leads to her pregnancy. Their two families are thrown into chaos and Jang Guk suffers a miscarriage due to an accident. Jang Guk’s mother sends her away to the U.S., hoping that her daughter would be able to lead a new life. They meet again 12 years later, but Jun Su does not recognise Jang Guk.