At Kaori Fujimiya have a secret. Her memories are erased every Monday. Because of this, she does not want to make friends, because... she will not remember them within seven days. Yuki Hase decided to make friends with Kaori, and knowing her secretHe still tries to get close to her, let her memories of him erased and every week. He wants that would someday she stopped to forget about him, and called him a friend.