During the summer holidays, energetic Hana Uzaki spent most of her time accompanying her lonesome upperclassman, Shinichi Sakurai. Now that school has resumed, Uzaki's teasing continues to ramp up, much to Sakurai's constant annoyance. Nevertheless, no amount of ridicule can damage the pair's relationship—which only seems to be getting better as their college days fly by!

Listless geek Mizuto Irido and introverted nerd Yume Ayai seemed like a match made in heaven, connected by their mutual love for literature. Unfortunately, their differences gradually grew, and they separated just after their middle school graduation. But, as if by divine comedy, the two find themselves reunited as step-siblings. A rivalry begins to brew between the former couple, both unwilling to acknowledge the other as the older sibling. In an attempt to "solve" this issue, Mizuto and Yume agree upon a rule: whoever crosses the boundaries of siblinghood norms loses, and the winner will not only be called the older sibling, but also get to make a request. However, now that they live under the same roof, the lingering memories they share start to influence their actions—possibly rekindling the feelings that may not have been fully extinguished in the first place.

Erika, the princess of the Magic Kingdom has come to Earth in order to find a human girl who looks just like her. That girl turns out to be Himeko Nonohara, a tomboy's tomboy. Erika must give Himeko a magical item she has created in order to prove her worth as a successor to the crown. Himeko must test this item, a hair ribbon that allows her to transform into any other person she sees, to see if it is worthy. The series follows Himeko's adventures and her budding romance with Daichi, the boy who discovers her secret.

Hikari is a young school girl who dreams of becoming a great champion in the sport of rhythmic gymnastics like her idol, Diliana Gueorguiva. Despite all her setbacks while performing, she works hard and with the help and support of Takaaki Oiishi (the best male gymnast of her school) soon becomes a member of the rhythmic gymnastics team in her school. She develops feelings for Oiishi, but she is not the only one—Hazuki Shiina, the best gymnast in the entire school, also has feelings for Oiishi. Soon a friendship between Hikari and Shiina develops, but also a rivalry as well in the sport and for the love of Oiishi. Hikari is also torn between her feelings for Oiishi and her conflicting feelings for Mao Natsukawa, an old childhood friend, who is also the lead singer of the band called Mr. D. He composes the music she uses while performing, and has been developing feelings for her since childhood.