In the kingdom of Kouka, a red dragon ruled in human form alongside four dragon-blooded warriors, ushering prosperity. Over time, this tale evolved into a children's legend. Princess Yona, pampered and in love with her cousin Su-won, enjoys a sheltered life under the care of her protector Son Hak. However, the peaceful facade shatters when Su-won orchestrates a coup, killing Yona's father. Fleeing with Hak, Yona faces a brutal reality as she aims to reclaim her kingdom. With guidance from an exiled priest revealing a sliver of hope in the form of the legendary dragon warriors, Yona embarks on a perilous quest to revive Kouka.