The kingdom of Kouka is blessed with a beautiful princess whose childlike innocence charms all who come across her. Named Yona, she has grown up sheltered in the royal palace, shielded from any danger that may befall her. However, all good things must come to an end. Yona's perfect world comes crashing down when a heinous act of treason threatens to erase all that she holds dear, including her birthright as the princess of Kouka. Left with no one to trust but her childhood friend and loyal bodyguard Son Hak, she is forced to flee the palace. Faced with the perils of surviving in the wild with a target on her back, Yona realizes that her kingdom is no longer the safe haven it once was. Free from the shackles of naivety, Yona vows to do everything in her power to become strong enough to crush her enemies. With Hak by her side, she must piece together the remains of an ancient legend that might be the key to reclaiming her kingdom from those who conspired to steal it from her.

At a remote hot springs lodge, Yona and the team rest. The boys are taking a bath with the exception of Ki-ja, who looks troubled. Jae-ha takes this chance to tease him, unwittingly finding a mark linked to the previous White Dragon—whom coincidentally is also Ki-ja's father—prompting Ki-ja to recall their complicated relationship. In another time and place, Son Hak and the dragons banter as they hold a drinking contest. As they start to doze off one-by-one, Zeno dreams of his past, where his abilities and experiences, both as a person and as the Yellow Dragon, are revealed.

The start of Hanae Ashiya's high school career has not been easy—he has spent all of the first week in the infirmary, and his inexplicable condition is only getting worse. The cause of his torment is the mysterious fuzzy creature that has attached itself to him ever since he stumbled upon it the day before school began. As his health continues to decline and the creature grows in size, Hanae comes across a flyer advertising an exorcist who expels youkai. Desperate and with nothing left to lose, he calls the number and is led to the Mononokean, a tea room which suddenly appears next to the infirmary. A morose-sounding man, Haruitsuki Abeno, reluctantly helps Hanae but demands payment afterward. Much to Hanae's dismay, he cannot afford the fee and must become an employee at the Mononokean to work off his debt. And to make things worse, his new boss is actually one of his classmates. If Hanae ever hopes to settle his debt, he must work together with Abeno to guide a variety of dangerous, strange, and interesting youkai back to the Underworld.

Despite being burdened with crippling debt to the morose Haruitsuki Abeno, Hanae Ashiya has come to enjoy his job as an exorcist. His ability to communicate with youkai has given him a sense of responsibility regarding the magical creatures, and he continues to work hard to send them to their true home in the Underworld. As Ashiya’s life finally stabilizes, the youkai threaten to upset it once again. Knowledge of his existence has begun to spread, and not everyone is happy to have a human working for the Mononokean, the interdimensional tea room. But one day, a simple visit to the Underworld draws the attention of those in power, and Ashiya soon learns that not every youkai is willing to go along with Abeno's plans.