"I thought I might be using a lifetime's happiness in a moment. I was that happy and she was that beautiful." A young boy stands on the red earth of Australia under its blue sky. It is 17-year-old Sakutaro Matsumoto. His time with the girl comes back to him. The colored sand runs through his hands and a tear appears on his cheek. He wakes up. It's 2004 and he is 34 years old and in Japan. He thinks "I have been in a world without her for 17 years." Returning home to see his old high school for the last time before it is demolished, Saku confronts anew the loss of the love of his life, Aki, to leukemia 17 years ago. Now a medical researcher at graduate school, he has been living as if half of him died with her since then.

While searching for his fiancee Ritsuko, Sakutarou rediscovers through flashbacks the void deep within him caused by the events from his high school days.