With the seniors having graduated from high school, the determined swimmers eagerly take on their futures with a dream to fulfill. Now attending Hidaka University in Tokyo, Haruka Nanase unexpectedly runs into Shiina Asahi, an old teammate and friend from his middle school days. Consequently, the troubling memories regarding his middle school swim team resurface, as it was a time when Haruka's views on swimming became negative and led him to quit the team. Haruka later reconnects with his other middle school classmates; all except for Ikuya Kirishima, who still resents Haruka for quitting the team, resulting in its disbandment. Aware of the issues between them, Haruka resolves to improve his friendship with Ikuya. However, he quickly realizes that making amends with an old friend isn't his only obstacle. Facing the reality and challenges of encountering higher calibre swimmers, Haruka must work hard to establish himself if he dreams of competing on an international level.

Kumiko Oumae, the third-year president of the band club at Kitauji High School, is filled with anticipation and anxiety. She wonders what kind of new members will come to the club, whether she will be able to organize everyone as the band leader, and whether she will be able to achieve her long-sought goal of winning a gold medal at the national competition. With these thoughts in mind, Kumiko spends her days struggling as the head of the club, but even as a player, a big obstacle appears in front of her. Mayu Kuroe transferred from a strong school that regularly participates in the national tournament. The instrument in her hand is the same as Kumiko's; the euphonium. She is a perfect girl, adored by everyone around her for her gorgeous tone, excellent playing skills, and gentle personality. However, the shadow that Mayu sometimes casts over Kumiko makes her feel indescribable. "Graduation" is approaching for these youths who have devoted themselves to the brass band. (Official Site, translated)

As a young boy, Prince Oscar Lyeth Increatos Loz Farsas was cursed by the Witch of Silence, rendering it all but impossible for any woman to bear him a child. After 15 years of fruitlessly seeking a way to lift the spell, Oscar resorts to enlisting the help of a different witch. To this end, he heads to the Azure Tower, home of the Witch of the Azure Moon. Ascending the tower is no easy task; for decades, no one has overcome the array of traps, puzzles, and enemies designed to repulse any challengers. Oscar, however, easily climbs to the top, where he meets the fabled witch, Tinasha. To the prince's surprise, despite being hundreds of years old, Tinasha looks like a beautiful young woman in her late teens. Oscar explains his circumstances to the witch, who quickly perceives the true nature of his affliction. Though she claims that undoing the spell would be tremendously difficult, Tinasha proposes a workaround—to find Oscar a partner capable of withstanding the curse's effects. Realizing that such a woman is right in front of his eyes, Oscar boldly tells the witch to marry him. Though he is promptly rejected, the young prince refuses to back down, and the two eventually reach an agreement: Tinasha will leave the tower and live with Oscar for the next year. As the two continue searching for a way to lift Oscar's curse, word of Tinasha's emergence from isolation spreads, catching the attention of all sorts of old acquaintances.

A new year signifies a new beginning, and that seems to be the case for Kitauji High School’s concert band. Following the graduation of the third-year seniors comes the entrance of the first-year juniors. The band members put in their utmost effort in practicing for their goal—to enter nationals. The now second-year Kumiko Oumae, along with her friends, is met with the new and quirky batch of first-years, resulting in friction and conflict between the band members. However, as time passes, their inner feelings slowly unravel, but not every conflict is as easy to solve as the other. The trust and bonds between the band members will be challenged as they push forward for their regionals.