Princess Yona of the Kingdom of Kouka, with her unusual red hair, has lived a comfortable life in Hiryuu Castle protected by her father King Il, who hates conflict, and her childhood friend and guard, the young general Hak. Yona is overjoyed when her cousin Soo-Won, whom she has loved since childhood, arrives for her sixteenth birthday banquet.

“We'll go anywhere as long as it means you'll live.” As Yona is dazed by the suddenly rebellion at the castle, Hak runs to her rescue. Also known as the “Thunder Beast of Kouka Kingdom”, Hak protects Yona, and with a single lightning-quick strike from his blade, he dispatches the mercenaries attacking them on after another.

Hak is accused of murdering King Il. In order to protect Yona and the Wind Village, he gives up his title of chief and decides to wander alone.

The blue dragon warrior retrieves his mask and begins digging a path out of the cave. The others join him and Hak starts digging from the outside. Hak finally breaks through and reunites with Yona. Yona again asks the blue dragon warrior to travel with them and he accepts. They set off, but Ki-Ja collapses from exhaustion so they stop to make camp. Yona gives the name "Shin-Ah", which she says means moonlight, to the blue dragon warrior. When they awake the next morning, Ki-Ja tells Yona he can sense the green dragon warrior.

"Miss, what do you want to do with the Four Dragons?" Yona and her companions continue their journey to find the fourth and final "Yellow Dragon" when they encounter a traveler named Jeno. He is the "Yellow Dragon" they have been seraching for.