Sentarō Kawabuchi is a hot-headed, energetic high-school delinquent in 1966 Kyushu, known for fighting, bluntness, and a fierce loyalty toward the people he cares about. He is an exceptionally passionate jazz drummer who is almost inseparable from his drums. Beneath his rough exterior, Sentarō is sensitive, affectionate, and deeply emotional, though he often struggles to express it with words. His closest friend and musical partner is Kaoru Nishimi, and the Mukae record shop and its basement are central places in his life.