One Week Friends Vol. 6 (manga)

Rebuilding her friendship with Hajime is what would make Kaori happiest...or at least, that's what Yuuki's convinced himself of. If it may help get her memory back, there's no chance Yuuki will stand in the way. But the sudden switch from his usual enthusiasm leads his friends to notice something is off...and more than that, Kaori comes to realize that she can't seem to get Yuuki off her mind...