Ishikura Leaf, a senior in high school, pretends not to notice the feelings of inferiority and unhappiness he has pushed into himself and enjoys his everyday life. He becomes friends with his shy classmate, Nakata Kurumi–Walnut; Takumi and Rizakura, who are also in his class, join him, and the four of them spend happy days together. Saved by Nakata’s smile, Ishikura gradually becomes attracted to her. However, one summer day, she loses her memory in an accident. Ishikura has many regrets, but one day he realizes that time has returned to the time before she lost her memory… Can fate be changed? Can a miracle happen? Will Ishikura and his friends be able to “use up” their irreplaceable days?