Princess Yona lives an ideal life as the only princess of her kingdom. Doted on by her father, the king, and protected by her faithful guard Hak, she cherishes the time spent with the man she loves, Su-won. But everything changes on her 16th birthday when tragedy strikes her family!

With war between the Kingdom of Kohka and South Kai close at hand, Yona strengthens her resolve on the battlefield. Meanwhile, South Kai forces take out General Geun-tae, which leaves Kin Province at a huge disadvantage. Will Hak fight at the front lines to help defend his nation?