高中时期，渡边的好友木月自杀了，这让他的恋人直子以及他的好友渡边都很痛苦。为了忘记这段痛苦的事情，渡边选择去东京上大学，远离伤心之地。渡边在大学偶遇了直子，此时的直子已经不似一年前那么活泼开朗，眉宇之间总是伴着忧愁。虽然在他们心理木月是无法避免的人，但是他们却都没有提及过木月。在二十岁生日这天，直子和渡边度过荒唐一夜，等渡边醒来却发现直子已经消失了。渡边的生活虽然回复了平静，但是对于直子的内疚还是萦绕在他的心里

  这天，渡边收到了直子的信，来到了直子生活的精神病院，渡边告诉直子会一直等待她。后来，渡边偶然遇到了一个性格开朗热情的学妹绿子，两人因为借书逐渐熟悉，随后开始交往，但是渡边内心里一直有直子的位置。

In high school, Watanabe's friend Kizuki committed suicide, which made his lover Naoko and his friend Watanabe very painful. In order to forget this painful event, Watanabe chose to go to Tokyo to go to university, away from the sad place. Watanabe ran into Naoko in college. At this time, Naoko was not as lively and cheerful as a year ago, and there was always sadness between her brows. Although Muyue was an unavoidable person in their minds, none of them mentioned Muyue. On the twentieth birthday, Naoko and Watanabe spent a ridiculous night, and when Watanabe woke up, he found that Naoko had disappeared. Although Watanabe's life has returned to calm, the guilt for Naoko still lingers in his heart

On this day, Watanabe received a letter from Naoko and came to the mental hospital where Naoko lived. Watanabe told Naoko that he would always wait for her . Later, Watanabe met a cheerful and enthusiastic school girl Midori by chance. The two gradually became acquainted with each other because of borrowing books, and then began to date, but Watanabe always had Naoko's place in his heart.