Imagine meeting your childhood friend after a decade of being apart. This is Mitsuya's reality as a newly transferred company executive who discovers that his neighbor in his new apartment is none other than Noboru, his older brother's best friend and his first love. Back in middle school, Mitsuya acted impulsively when he kissed Noboru and pushed him away, leading to a long-lasting regret. However, being reunited with Noboru reignites Mitsuya's passions as if no time has passed at all.