Akutsu Masatora is a demon who has infiltrated a high school in the human world. His goal is to find candidates to aid Hell in the fight against their natural enemies, the angels of Heaven. Assigned a seat next to Lily Amane, another student who transferred here not long ago, Akutsu falls prey to her beauty and decides to recruit her to his cause. But there's more to Lily than meets the eye, and Akutsu not only finds himself an accomplice to one of the very enemies he is supposed to defeat, but he also might have developed feelings for her.

Having just moved from Tokyo to Hokkaido, high school student Tsubasa Shiki decides to explore the picturesque winter landscape he could never experience in the nation's capital. It only takes a moment for Tsubasa's idealized view of Japan's northernmost prefecture to crumble, as the sheer cold and frigid air quickly overwhelm him. While trying to find the way to his new home, Tsubasa runs into Minami Fuyuki—a talkative and friendly Hokkaido native who, despite the cold, is wearing a short skirt. The girl wastes no time in striking up a conversation, and Tsubasa comes to realize that the winter weather is not all that is too much for him to handle. The next day, Tsubasa is shocked to learn that not only is Fuyuki in his class, but her seat is also right next to his. Swept along by Fuyuki's persistent advances, the young man soon becomes captivated by both life in Hokkaido and the beautiful girl determined to get closer to him. As he deepens his relationship with Fuyuki and meets other fashionable girls from his school, Tsubasa finds out that Hokkaido gals truly are adorable.

The princess who's been held captive by the Demon Lord's army is scheduled to be executed by the Demon Lord's relentless torture!

The year is 2222. It has been years since Tears of the New Moon, a mysterious rain, poured and wiped out almost the entire human race. The poisonous rain gave birth to deformed creatures devouring humans, and humanity fled from the danger. As means for survival, the humans then build an underground haven; Amasia. In this newly built dystopian city, in a pursuit of maintaining their existence, they run into an Artificial Intelligence named Magus. Not knowing how things will work between them, the story of how Humans and AI coinciding and trying to find their truths begin.