Given S01E01 - Boys in the Band

Ritsuka Uenoyama meets Mafuyu Sato one day in his normal napping spot. Ritsuka ends up fixing Mafuyu's guitar, which leads to Mafuyu pestering Ritsuka to teach him guitar over and over. Ritsuka declines over and over but somehow, after seeing how passionate Mafuyu is about learning guitar, Ritsuka starts to remember how he felt when he first started playing music.