The story of Princess Pyeonggang who was born as a princess but raised to be a soldier for Goguryeo. She dreams to be the first female Taewang of Gorguryeo but is confused about the new feelings experienced after meeting On Dal.

Chul-soo is a man with an intellectual disability. One day, Chul-soo finds out that a young girl, Saet-byul, who is in hospital is his daughter. And soon, Saet-byul sneaks out of the hospital and travels by herself to a faraway city for her friend's birthday. As Chul-soo accompanies Saet-byul's journey, friendship develops between the two.