One day, high-school boy Yamada bumps into the beautiful girl Shiraishi on the stairs (literally), and their lips touch as they fall. When they regain their wits, they realize that they have swapped bodies. As time progresses, the two realize that this is not the only mysterious happening in the school.

Tsutsui Hikari (a.k.a "Tsuttsun") is a high school student who is content with his virtual life of anime and video games. One day, he gets stuck cleaning the pool with Iroha, a real live girl who is stylish, sassy and known to be easy with boys ... and she aggressively approaches him! Tsuttsun, who has few friends and lives in his own world, finds himself smitten by the confident and wild Iroha ... and his whole world is turned upside down!! It's the awkward and pure love story of a boy who experiences relationship for the first time.

On a continent ruled by chaos, the Lords have the power of a holy seal that can calm the chaos and protect the people. However, before anyone realizes it, the rulers cast aside their creed of purifying the chaos, and instead start to fight each other for each other's holy seals to gain dominion over one another. Siluca, an isolated mage who scorns the Lords for abandoning their creed, and a wandering knight named Theo, who is on a journey to train to one day liberate his hometown, make an everlasting oath to work together to reform this continent dominated by wars and chaos.

Lee Young-Joon's family runs a large company and he works as the vice-president of the company. He is smart, rich and handsome, but he is arrogant. His secretary is Kim Mi-So. She has worked for him for years and she is perfect for him, but Kim Mi-So decides to quit her job.

Ao Horie’s father, a popular erotic fiction author, chose Ao’s name because A stands for “apple” and O stands for “orgy”! Desperate to escape her father’s legacy and get into a prestigious university, Ao devotes herself to studying instead of pursuing romance. She has no time for boys, but there’s just one problem: Kijima, her handsome and popular classmate, just confessed his love to her! And to make matters worse, she can’t stop thinking dirty thoughts about him! Looks like escaping her father’s influence will be harder than she thought…