Out in the countryside stands a sweet shop run by the Shikada family for nine generations: Shikada Dagashi, a small business selling traditional Japanese candy. However, despite his father's pleas, Kokonotsu Shikada, an aspiring manga artist, adamantly refuses to inherit the family business. However, this may start to change with the arrival of the eccentric Hotaru Shidare. Hotaru is in search of Kokonotsu's father, with the goal of bringing him back to work for her family's company, Shidare Corporation, a world famous sweets manufacturer. Although the senior Shikada initially refuses, he states that he will change his mind on one condition: if Hotaru can convince Kokonotsu to take over the family shop. And so begins Hotaru's mission to enlighten the boy on the true joy of delicious and nostalgic dagashi!

The Kazama Family—a gang of three wannabe delinquents and close friends, spearheaded by Kenji Kazama, is trying to make a name for themselves at Fujou Academy. On the first day of the term, the gang finds themselves putting out a fire in the Game Development Club. Instead of thanking them, the eccentric club members attack and knock out Kenji's two friends, forcing Kenji to fight for his life. Failing to escape, the gang leader is coerced into joining the Game Development Club. As he settles in, Kenji gets to know the four girls responsible for his provisional membership—student council president and general tyrant Chitose Karasuyama, spirited tomboy Sakura Mizukami, negligent club advisor Minami Oosawa, and the school's infamous shadow leader Roka Shibasaki. Throughout the Game Development Club's constant shenanigans and his desperate attempts to leave the club, Kenji begins to realize that he may be actually enjoying himself.

During a Literature Club meeting, the four club members—along with their faculty adviser's niece—suddenly find themselves with supernatural powers. Now capable of fabricating black flames, resident chuunibyou Jurai Andou is the most ecstatic about their new abilities; unfortunately, his own is only for show and unable to accomplish anything of substance. Moreover, he is completely outclassed by those around him: fellow club member Tomoyo Kanzaki manipulates time, Jurai's childhood friend Hatoko Kushikawa wields control over the five elements, club president Sayumi Takanashi can repair both inanimate objects and living things, and their adviser's niece Chifuyu Himeki is able to create objects out of thin air. However, while the mystery of why they received these powers looms overhead, very little has changed for the Literature Club. The everyday lives of these five superpowered students continue on, albeit now tinged with the supernatural.

Now that Kumiko Oumae has enrolled in Kitauji High School, she hopes to forget about her past. Despite her desire for a fresh start, she gets dragged into the school's band club by her new friends—Sapphire Kawashima and Hazuki Katou—and is once again stuck playing the euphonium. As the band currently stands, they won't be able to participate in the local festival, Sunfest, let alone compete at a national level. The band's new advisor, Noboru Taki, gives them a choice: they can relax and have fun, or practice hard and attempt to get into nationals. Not wanting to repeat her mistakes from middle school, Kumiko is doubtful as to whether they should try for nationals. Amidst the chaos, she learns that her old bandmate, Reina Kousaka (who she had a bitter relationship with) has joined Kitauji's band club. Under the pressure of Noboru's strict training, Kumiko and her bandmates must learn to overcome their struggles and find success together.