In the summer of 1966, Kaoru Nishimi, a timid freshman from Yokosuka's high school, had to move to Kyushu due to his father's job. Nevertheless, his life takes a dramatic turn when he befriends Sentaro Kawabuchi, the notorious school delinquent. Thanks to Sentaro's influence, Kaoru discovers his love for jazz, finds a faithful friend, and experiences the thrill of creating music with a partner. Apart from the main protagonists, the story also introduces Ritsuko, Sentaro's childhood friend, who runs her father's music store and is known for her kindness. The enigmatic senior Yurika and respected member of their social circle, Brother Jun also feature in the narrative. The setting is a coastal town that effortlessly blends American culture, and the story follows a group of youngsters as they form indestructible bonds of friendship, love, and music.