《太阳》以近未来的日本为舞台，描写了只能在夜晚生活的新人类与在太阳下生活的旧人类之间的对立和融合，是一部追寻生存意义的人情派作品。曾执导过《Joker Game》等作品的入江悠携手年轻的演技派神木隆之介、门胁麦共同合作，彼此之间互称战友。
An affluent medical professor, Komiya, and his bossy wife, Tokio, are to look after Setsuko, their high-spirited niece from Osaka. Setsuko is a liberated woman who does what she wants, including smoking, even though she is a minor. On Saturday, the professor does not feel like going to his weekend golf game, but his wife packs him off anyway. So he leaves his bag at the apartment of his student Okada, and goes to a bar with a friend. Setsuko traces him there, and insists that he take her to a geisha house. When she gets rather tipsy, the professor calls Okada to take her home, while he sleeps at Okada's. The wife becomes suspicious of Setsuko when she sees Okada bringing her home, and also of her husband when she discovers that he did not go golfing.
