In the land of Ryoza, the neighboring provinces of Shin-Ou and Tai-Kou have been at peace. Queen Shinou is the ruler of Ryoza and her greatest general, Grand Duke Taikou, defends the kingdom with his army of powerful war-lizards known as the "Touda." Although the two regions have enjoyed a long-standing alliance, mounting tensions threaten to spark a fierce civil war. Within Ake, a village in Tai-Kou tasked with raising the Grand Duke's army, lives Erin, a bright girl who spends her days watching the work of her mother Soyon, the village's head Touda doctor. But while under Soyon's care, a disastrous incident befalls the Grand Duke's strongest Touda, and the peace that Erin and her mother had been enjoying vanishes as Soyon is punished severely. In a desperate attempt to save her mother, Erin ends up falling in a river and is swept towards Shin-Ou. Unable to return home, Erin must learn to lead a new life with completely different people, all while hunting for the truth of both beasts and humanity itself, with tensions between the two regions constantly escalating. [Written by MAL Rewrite]

A catastrophic earthquake has left Tokyo, and most of the Earth for that matter, under the sea. Aika is a salvager who retrieves various remains from the watery ruins. When Aika accepts the dangerous mission of locating and obtaining the mysterious Lagu, she discovers that she's not the only one after it.

A bonus episode about Aika and company moving to a new office.

The stage is Ayanagi City, a city near the Japan Sea. It is a futuristic city that was built to carry out the recovery from the calamity caused by the "Apathy Syndrome" ten years previous. High school student Shin Kanzato with his little brother Jun, meet with their elder brother Ryou, who is the chief of the Ayanagi City Police, again after ten years. At that time, a series of strange incidents happen in Ayanagi City such as the crew of a submarine that suddenly disappears while in their submarine, or a spiritless symptom which disturbs the world after ten years, or the case of the inside out corpse where a student took on a cruel appearance. Ryou tracks down the organization behind the string of incidents, and having become involved in the incidents, Shin awakens the "Persona." (Source: Wikipedia)