In a city inhabited by youkais and humans, Kotoha is an exception, becoming a half-youkai when she was struck by a mysterious lightning when she was a kid. But when she is struck once again, her powers go out of control and start threatening the city until her friends come to save her.

The Hiizumi Life Counseling Office is assisted by a pair of Ogre siblings, Kyōsuke and Tōka Kishi, who must control their massive strength to not injury those arround them. After an incident with Tōka makes her regret her condition, Kyōsuke lashes his fury at Akina, whom he believes is yet to awaken the power of "Tuning" that runs in his family and could help Tōka, until Akina prove him otherwise.

Kohime Sakurano, a cousin of Hime, intends to run for mayor in a neighboring town and the current mayor Morino comes with an underhanded scheme to prevent it.

Hime and her friends confront an elusive man to rescue Kohime but the situation becomes drastic when they fall under the influence of a barrier that weakens their youkai powers.

With Hime in no condition to fight, Akina and Kyōsuke distract the enemy while the rest of the team look for the source of the barrier to disable it.

With the barrier destroyed and Hime unlocking her true powers, the gang drives the enemy to a corner and rescue Kohime after Morino reforms. However, the man reveals himself to be Enjin Hiizumi, a foe far more dangerous than they believed.

After the last crisis is averted, peace returns to Sakurashin. However, Enjin is still on the run and plans to enact revenge on the city. Akina and Hime are summoned by the senate to discuss the situation and are angered with their purpose to sacrifice the youkai in the city to stop Enjin's plans.

Following the events of Hoshi no Umi, Zakuro attempts to adapt herself to her new life as a resident of Sakurashin. While Akina pays a visit to the memorial to his grandfather and all the youkai tuned by the Hiizumi family, he is confronted by Enjin, who attempts to possess his body, but is saved by members of the senate, but little they know that Enjin soon after learns to control the same power they used to defeat him and becomes an even more dangerous threat.

When Hime catches a cold, her friends keep her company to ensure that she will not overexert herself. Some time later, the mayor pays a visit to the local doctor, V Juri F for a checkup. As Juri reminisces about when she moved to Sakurashin, she is unaware that her younger sister is the next of Enjin's youkai hunters who are preparing to attack the city.

Believing that her sister Lila is dead, Juri tells Hime the story of their childhood together. However, when Juri reveals that she has no intention to see her sister if possible, Lila appears and attack them.

Lila restrains Juri and threatens to kill Hime, while her friends arrive to help them. Certain that Enjin is plotting something else, Akina starts looking for him while Juri and the others attempt to dissuade her sister.

While Juri reconcile with her sister, Akina confronts Enjin, and learns the true reason for his grudge on the city and gets himself in a pinch when the enemy shows a glimpse of his true powers.