Four boys named Haruka, Makoto, Nagisa and Rin all participated in a swimming tournament shortly before graduating elementary school and later parted ways. Years later, they reunite when Rin challenges Haruka to a race and wins. Not wanting to be defeated so easily, Haruka gathers Makoto and Nagisa and a new recruit named Rei to form the Iwatobi High School Swimming Club.
The boys of summer are back. Haru, Makoto, Nagisa, Rei, and Rin are reunited and the competition is about to get fierce. After the last swimming meet, the bonds of friendship have only gotten stronger, and with each passing day the boys continue to grow. This summer brings new rivals and new challenges.
Four men are assigned to the prison: Jūgo, a man who attempted to break out of prison and ended up extending his jail time; Uno, a man who likes to gamble with women; Rock, a man who likes to get into fights; and Nico, a man who likes anime.
After experiencing a bizarre dream, Madoka Kaname, a kind 14-year-old girl, encounters a magical creature named Kyube. Madoka and her friend Sayaka Miki are offered the opportunity of gaining magical powers if they agree to make a contract with the strange little being. He will also grant them one wish, but in exchange they shall risk their lives by accepting the responsibility of fighting witches. Invisible to human eyes, witches are catalysts of despair in the areas they inhabit. An ally of Kyube, a magical girl named Mami Tomoe, befriends and encourages the two girls to accept the contract. For an unknown reason, another magical girl named Homura Akemi is determined to prevent Madoka from accepting the deal.
In Oshima the happy, carefree 14-year-old Akane Isshiki lived a poor but well-loved life together with her reliable little sister, Momo, who does all the housework, and her grandfather, Kenjirō, a genius inventor who only created useless devices. When the weather is clear, they can see the artificial island, Blue Island, across the sea. In the center of that island rises the revolutionary Manifestation Engine, a discovery that solved the world's energy problems, and leads to some major problems.
Ryuu Yamada is known as a delinquent in his high school; he has been bored of classes after one year of attending school. One day, he accidentally falls from a flight of stairs onto Urara Shiraishi, the ace student of the school. Yamada wakes up to find that he has swapped bodies with her! The two try to reverse the change and discover that kissing triggers the body swap. On the suggestion of student council vice-president Toranosuke Miyamura, they revive the Supernatural Studies Club. The club encounters other "witches" with different powers that are activated with a kiss!
Right after starting middle school, Akari Akaza joins the Amusement Club which is composed solely of her two childhood friends, Kyouko Toshinou and Yui Funami. Chinatsu Yoshikawa, Akaza's classmate, becomes a member after finding out about the dissolution of the Tea Club. The Amusement Club, situated at the tea room facility since the Tea Club disbanded, has no clear purpose, being free for the girls to do whatever they want.