Four years ago, Zero (Shigeaki Kato), a graduate student, came to see Mitsuru (Keiichiro Koyama), who runs a pension while aiming to become a photographer, for his annual summer stargazing. That summer, Mitsuru proposes to Megumi (Noriko Iriyama) with Zero as a witness. She took many pictures of her happy self on camera. Later, Mitsuru's photo from that time will win the grand prize in a competition. He is a genius who lives in the great outdoors, and there is also talk of releasing a photo book about him. Mitsuru declares to Zero that she sold her pension in order to work in Tokyo. However, Zero's feelings are complicated... On the day of his proposal, Mitsuru forgot his ring and went back to get it, but she left her camera with Zero. In fact, what won the award was a photo that Zero casually took of Megumi during that time. Mitsuru is shocked when the editor, Saeki (Kenta Satoi), who doubts his talent, points this out. Then he notices something strange in the photo...
4年前、写真家を目指しながらペンションを営むミツル（小山慶一郎）の元に大学院生のゼロ（加藤シゲアキ）が毎年夏恒例の星の観察のためにやってきた。
その夏、ゼロが立会人となりミツルは恵（入山法子）にプロポーズ。幸せそうな恵を何枚もカメラにおさめた。
後日その時の一枚が、コンクールで大賞をとり舞い上がるミツル。大自然に暮らす天才として写真集発売の話も進んでいく。
ミツルは東京で活動するためペンションを売ったとゼロに宣言。
しかしゼロの胸中は複雑で…。
あのプロポーズの日、指輪を忘れて取りに戻ったミツルはゼロにカメラを預けた。実は受賞したのは、その間、ゼロが何気なく恵を撮った一枚だったのだ。
才能を疑いだした編集者の佐伯(佐戸井けん太)にその事を指摘されたミツルは衝撃を受ける。そして写真の中のある異変に気付いてしまい…。
