Yuki Hase befriended a lonely girl classmate when he notices that she's always alone. Upon knowing the girl, he found out a serious matter about her that can either make him put a space between them, or make them closer to each other.

Similar to Forget Me Not (2015), One Week Friends takes the viewer to a high school where a boy is fascinated with and falls for a cute class-mate of his. The girl is a loner who has no friends. She gets approached by class-mates and is asked to after school activities, but is resolute in always saying 'no.' She has amnesia and only remembers events, names and faces one week at a time. Not to be put off her class-mate is determined and even comes up with a clever idea for them to remain friends and acquainted.—aghaemi