On Monday, Kaori Fujimiya rejects Yuki Hase's proposal of friendship. Feeling disheartened, Yuki's friend Shogo Kiryu advises him to ask Kaori for the reason that they can't be friends. However when he tries doing so, Kaori feigns illness and ignores him. On Tuesday, Yuki goes to the rooftop and sits down to lunch with Kaori, however she blatantly puts that she cannot have any friends. Not giving up, Yuki compromises that they have lunch the next day as acquaintances only. On Wednesday, Yuki meets with Kaori and they talk about the things they do after school. After having lunch on Thursday, Kaori excitedly shows Yuki a flyer for a crêperie but stops herself, declaring that they aren't friends. As they continue their discussion, Yuki asks for Kaori's view on friendship. Finally, as Friday arrives, Kaori tearfully explains to Yuki that she loses the memories of people she gets close to every Monday, leaving the latter in sheer disbelief. Unsure of what to do, on Saturday, Yuki asks for Shogo's advice and he encourages Yuki to pursue Kaori. Finally, on Monday Yuki approaches Kaori in class and heartbreakingly confirms the truth of her words when she looks at him with a dark expression. However, believing that Kaori really wants a friend, Yuki asks her to be friends.