The story takes place in the 21st century during a solar eclipse. The focus is on a young girl named Ko Ha-jin, who finds herself transported to the past, during the Goryeo Dynasty. She wakes up in the year 941, inside the body of a sixteen-year-old noble girl named Hae-su. However, Ko Ha-jin retains memories of everything that happened to her in her previous life. Unfortunately, she has no way of returning back. The heroine is forced to adapt to the realities of the ancient world.