Atop a hill overlooking a seaside port sits a boarding house named Coquelicot Manor. Since the building is run by her family, Umi Matsuzaki carries out many of the duties involved in managing the small establishment, such as preparing meals for her fellow boarders. When she isn't at home, she is a student at the local high school—one that is currently dealing with a small crisis. In anticipation of the upcoming Olympic Games, a beloved old clubhouse is set to be demolished to make way for a modern building. As a result, a large part of the student body has banded together, working tirelessly to prevent this from happening. Umi finds herself helping the newspaper club to spread information about this cause where she befriends Shun Kazama, whom she gradually begins to fall in love with. But Shun is an orphan who doesn't know much about his origins, and when the two begin searching for clues to the boy's past, they discover that they may have a lot more in common than either of them could have thought. [Writtten by MAL Rewrite]

In a world covered by an endless sea of sand, there sails an island known as the Mud Whale. In its interior lies an ancient town, where the majority of its inhabitants are said to be Marked, a double-edged trait that grants them supernatural abilities at the cost of an untimely death. Chakuro is the village archivist; young and curious, he spends his time documenting the discovery of newfound islands. But each one is like the rest—abandoned save for the remnants of those who lived there long ago. For the first time in six months, another island crosses the horizon, so Chakuro and his friends join the scouting group. During the expedition, they find vestiges of an archaic civilization. And inside one of its crumbling remains, Chakuro discovers a girl who will change his destiny and the world inside the Mud Whale as he knows it.

Kyou kara Maou! revolves around Yuri Shibuya, your average Japanese teenager. One day, Yuri sees a classmate being harassed by bullies. Thanks to this intervention, his friend is able to escape, but unfortunately Yuri becomes the new target of the bullies in the process and gets his head shoved into a toilet. But instead of water, the toilet contains a swirling portal that sucks him into another world, largely resembling medieval Europe. There, he is told that he will become the next Demon King due to his black hair and black eyes, traits only possessed by the demon's royal lineage. Yuri's arrival is met with some skepticism by some of the demons, who view him as unworthy to be their king. However, after Yuri wins a duel by utilizing his magical powers, the demons slowly begin to acknowledge him as their monarch. Yuri must now learn what it takes be a true Demon King, as he tries to keep the peace between demons and humans in this strange new realm.

Life has returned to some form of normalcy after the end of the series, and so His Majesty Yuuri Shibuya travels to oversee how things are going. While doing so, he runs into the king of Small Shimeron--Sararegi. But it seems there may be something more to him than the friendly king he presents himself as. Yuuri go back to Shimaron to relax and meet some friends, when the king of Little Shimaron suddenly joins the group and wants the Maou to come to his country. The Original king sends a message to Yuuri's brother and his friend that Yuuri is in trouble. (Source: ANN)