Haruhi Fujioka is a studious girl who has recently enrolled at the prestigious Ouran Academy. One day, while looking for a quiet and peaceful place to study, she stumbles across a seemingly unused music room. Upon entering, Haruhi is welcomed by the members of the well-known Host Club: a club in which attractive boys amuse girls from across the entire school. However, when Tamaki Suou—the founder and president of the club—startles the bright scholarship student, she accidentally breaks an expensive vase. With repayment looking difficult for Haruhi, the Host Club members come up with the perfect solution to the girl's problem: work for the club and ultimately become a Host herself! Mistaken for a boy by her peers, Haruhi has to entertain various female students while coping with her fellow Hosts' extravagant personalities.

When Ryuu Yamada entered high school, he wanted to turn over a new leaf and lead a productive school life. That is why he chose to attend Suzaku High School, where no one would know of his violent delinquent reputation. However, much to Ryuu's dismay, he is soon bored; now a second year, Ryuu has reverted to his old ways—lazy with abysmal grades and always getting into fights. One day, back from yet another office visit, Ryuu encounters Urara Shiraishi, a beautiful honors student. A misstep causes them both to tumble down the stairs, ending in an accidental kiss! The pair discover they can switch bodies with a kiss: an ability which will prove to be both convenient and troublesome. Learning of their new power, Toranosuke Miyamura, a student council officer and the single member of the Supernatural Studies Club, recruits them for the club. Soon joined by Miyabi Itou, an eccentric interested in all things supernatural, the group unearths the legend of the Seven Witches of Suzaku High, seven female students who have obtained different powers activated by a kiss. The Supernatural Studies Club embarks on its first quest: to find the identities of all the witches.

Most people would prefer being the protagonist of a world full of adventure, be it in a game or in another world. But, unfortunately, a certain girl is not so lucky. Regaining the memories of her past life, she realizes that she was reborn in the world of Fortune Lover—one of the games she used to play. Unfortunately, the character she was reincarnated into—Catarina Claes—is the game's main antagonist, who faces utter doom in every ending. Using her extensive knowledge of the game, she takes it upon herself to escape from the chains of this accursed destiny. However, this will not be an easy feat, especially since she needs to be cautious as to not set off death flags that may speed up the impending doom she is trying to avoid. Even so, to make a change that will affect the lives of everyone around her, she strives—not as the heroine—but as the villainess.

In a futuristic society, Japan has implemented a complex system referred to as The Red Threads of Science to encourage successful marriages and combat increasingly low birthrates. Based on a compatibility calculation, young people at the age of 16 are assigned marriage partners by the government, with severe repercussions awaiting those who disobey the arrangement. For Yukari Nejima, a teen that considers himself average in every way, this system might be his best shot at living a fulfilling life. However, spurred by his infatuation for his classmate and long-time crush, Misaki Takasaki, Yukari defies the system and confesses his love. After some initial reluctance, Misaki reciprocates his feelings in a moment of passion. Unfortunately, before the two can further their relationship, Yukari receives his marriage notice. He is then thrown into a confusing web of love and lies when his less-than-thrilled assigned partner, Ririna Sanada, becomes fascinated with his illicit romance.