Dong-chang-saeng plot
"He'll stop nothing to save her."
To save his sister's life, Myung-hoon decides to volunteer as a spy and infiltrate South Korea as a defecting student. While in high school in the South, he meets another girl who, like his sister, is also called Hye-in, and he rescues her when she is attacked. However, the South Korean authorities soon discover the true reason for Myung-hoon's stay and begin to track him down. At the same time, the North Korean government sends an assassin to take out Myung-hoon before his cover is revealed. His chances of surviving this bloody cat-and-mouse game are diminishing by the day…