Yuuki Hase desperately wants to be friends with Kaori Fujimiya, the girl in class who seems to always be alone. Just when he thinks they've hit it off, she tells him her secret: Every week, her memories reset. Yuuki resolves to befriend her as many times as it takes, but is he prepared for how much it will hurt to be one-week friends...?

Even though Kaori's memories were washed away each week, it was clear that Yuuki remained tucked away somewhere in her heart...or at least, that's how it felt before. Having Kaori treat him the way she did that very first time they spoke is painful, but Yuuki isn't willing to give up on their one-week friendship - even if it means confronting Kaori's childhood friend, Hajime. Meanwhile, when Saki demands that Shougo own up to her reliance on others, things might start to change between the two of them...

Even with Yuki's memory of Kaoru disappearing each Monday, he continues to persist in befriending her every week! Each time their friendship deepens, despite Yuki's condition. Can Kaoru make an impression on her with his willfull question, "Would you like to be friends?"

After Hajime reveals new information about the incident that triggered Kaori's memory loss, Yuuki decides to stop running away...but he's unsure of what he can do to help the childhood friends reconnect and to bring Kaori happiness. In the meantime, Kaori grows uneasy, since the Yuuki who's been acting cold and distant toward her doesn't seem like the same boy from her journals. When the two finally face each other and their feelings, in what way will it affect their one-week friendships to come? See how uncovering the past will change the future for Yuuki, Kaori, and friends in the final volume of One Week Friends!

Hearing Hajime's story about the friendship he once shared with Kaori leads Yuuki to help reunite the pair. With a new old friend now in the mix, Kaori needs more than one diary to avoid starting every week from zero. But when Hajime and Kaori start to display a special bond that can be shared only by longtime friends, Yuuki is forced to wonder exactly what sort of relationship he wants with someone whose memory of him lasts only so long...

Takashi is busy returning the names his grandmother trapped in her book and helping the local yokai with their problems. But he has to put his good deeds on hold when a black Nyanko Sensei look-alike snatches the Book of Friends! Takashi and the real Nyanko trail the bad cat to a secret yokai meeting. Will they be in time to stop the impostor's wicked plans?! -- VIZ Media

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...