Erin is a 10-year-old girl and her mother Soh-yon, a beastinarian who cares for Tohda in the Tai-Koh region in the Village of Ake. After Erin tells her mother that she wants to be a "Tohda doctor" like her, Soh-yon reminds Erin that Tohda are wild animals, something she has yet to learn.
While Erin is with her friends caring for the village goats, she notices a poisonous plant called capracide growing in the fields that could kill the herd. She asks the villagers to help her remove it.
The village prepares to welcome the Grand Duke and a relative of the queen to watch the Tohda's training.
Erin hears that Shaju's older sister has been engaged while watching the dowry from the groom's village enter the main gates.
The village prepares for the annual egg hunt in which the village men travel to the swamps to find Tohda eggs.
On a rainy night, Soh-yon is summoned to the underground Tohda ponds. There, Soh-yon finds all the Kiba, the Grand Duke's most prized Tohda, dead...
Soh-yon is condemned by executed after the Grand Duke's Kiba mysteriously dies. Erin jumps into a lake full of Tohda in an attempt to save her bleeding mother, but her mother has her taken to safety.
Joh-on, a beekeeper in the Shin-Oh region, finds Erin unconscious, floating in the river. He rescues her and nurses her to health, as she attempts to cope with the loss of her mother.
While staying with the beekeeper Joh-on, Erin decides to have Joh-on teach her to be an animal breeder and live with him.
Erin and Joh-on both go to the capital to shop for supplies.
Joh-on decides to have his family move to his summer cottage in the mountains. He decides to teach Erin and his children about breeding animals.
Erin finds a large, silver feather in a tree close to Joh-on's summer cabin high in the mountain. Joh-on tells Erin about the king of beasts, the Ohju, and Erin's interest in the Ohju begins to grow.
While climbing down a cliff, Joh-on slips and falls onto a ledge of the steep cliff. Erin goes out and finds the hurt Joh-on, and decides to stay with him until the morning.
The first recap episode; Nah-son, a scout sent by the Mist Elders to watch over Soh-yon, tells the Elders what happened to Soh-yon and her daughter Erin.
Joh-on's son comes and asks his father to become a teacher again. When his son learned that his dad had a young girl living with him, he offered to have her come live with them and have Erin marry-off.
While in town, Erin accidentally breaks the harp Ia-lu the Seh-zan gave to her when she was 10.
At a festival celebrating the Shin-Oh's birthday, Ia-lu the Seh-zan, along with a baby Ohju, are injured by an assassin's arrow during an attempt on the Shin-Oh's life.
Erin passes the entrance exam and becomes a Kazalm student. There, she meets the Reverend of Teachers at Kazalm, Esal, who is also happens to be an old friend of Joh-on. And with this, Joh-on and Erin say their teary eyed goodbyes.
Struggling to fit in with her fellow students, Erin is comforted by a new friend that tells her she can just be herself.
Erin's Professor, Esal decides to let her take care of the baby Ohju Lilan after meeting her. She says that Tomura, the person who is currently talking care of Lilan, is not ready to take care of her yet.
Erin tries to take care of a stubborn Lilan and struggles to put her to sleep.
Erin goes to the capital with Tomura and her two followers, Nuk and Mok, to go back to the Yantoku harp shop and stumble upon Ia-lu who is fighting against two unknown assailants.
The teachers of Kazalm discuss Erin's attempts to communicate with Lilan using the harp.
The Grand Duke's two sons Shunan and Nugan decided to take their own paths after settling it with a duel.
While helping out in Kazalm, Nuk and Mok accidentally lose some gold. Upset at their own actions, they try to earn the money back and make Erin proud.
Erin fails a quiz but must re-take it in order to enter high school in Kazalm. Meanwhile, Erin finds out that she means more to Lilan than ever before.
Erin starts having nightmares about her mother, Soh-yon who was being taken into "Hikara" the dark part of the afterlife.
One morning Erin learns that Joh-on passed away from heart disease. Erin becomes sad but Professor Esal takes her to Joh-on's hideout when they were still students.
Erin and Lilan bond over grooming but Erin accidentally hurts Lilan which causes an uneasy friendship that they have to fix.
A recap episode on Erin's stay at Kazalm; a four year time-skip where Erin is now 18 and a college student.
A new teacher, Kirik, comes to Kazalm Academy from the capital.
Erin is confronted by Nah-Son, an agent sent by the Mist Elders to watch over her. He asks Erin to make a difficult decision that could change the fate of the Ohju.
Erin informs Professor Esal that Lilan can fly. Fearing that she might fly away from Kazalm, Erin has to make a decision for her's and Lilan's sake.
An injured Ohju is delivered from the Lazal rescue center. Erin realizes the Ohju is something from her past...
Another injured Ohju is delivered to Kazalm, this time it is a wild male who they decided to call "Eku." After a full day with the angry Ohju, Erin manages to gain his trust and communicate to him with her harp.
Erin and the others take the Graduation Test with all of them passing with Erin taking top scores.
Erin officially becomes a Master in the fall and new students come to Kazalm. Of the new students, a girl named Shiron, calls Erin her rival and will stop at nothing to prove herself.
The Shin-Oh decides to visit Kazalm to see Aru. Esal and the faculty decide to keep the Shin-Oh from finding out that Erin uses the harp to communicate with Eku and Lilan.
While going back to the palace by boat, the Shin-Oh is suddenly attacked by an army of Tohda in the river. It's up to Erin and Lilan to save them but will they do it in time?
The Shin-Oh is knocked unconscious after the sudden Tohda attack on the boat-ride to the palace while Erin has other ideas about the attack.
Erin is called to the Kazalm palace, and is asked to accompany the Shin-Oh back to the royal palace with Lilan as bodyguards.
Word of the Shin-Oh's sudden death on the way back to the palace has spread, and everyone mourns for the death of their beloved Shin-Oh.
Beastinarians from Lazal come, learning about Erin's ability to tame Ohju without the use of a Silent Whistle, and confront Erin about using one as required by law.
As the war between the Shin-Oh and the Tai-Koh regions begins, Erin is called to the palace by Dahmiyah. He orders Erin to create a battalion of Ohju to use for the war. Will Erin oblige?
Back at the Royal Palace, Kahil tells Ia-lu that Dahmiyah was to wed Shin-Oh Seimiyah.
After being poisoned by Dahmiyah and injured by the Psi-Gamul, Ia-lu seeks refuge at Lazal with Erin.
While at the Forest of Purification, Seimiyah is confronted by a large Ohju in the mist.
It's the day of the meeting between the Shin-Oh and Tai-Koh. They decide if there will be a war or not.
The Tai-Koh's Touda troop advances toward the Shin-Oh, but Seimiyah refuses to go to war with Shunan.
In the final episode, Erin flies Lilan into the battlefield and successfully destroys the Touda army Dahmiyah made.
