天日（周润发饰演）是来自外星球拥有超能力的人，一次偶然的机会降落到了地球找水，可是四处都没有水源，眼看着就要因为缺水而导致死亡，幸亏被郭克松给救了。从此之后天日为了报答郭克松的救命之恩，就多次利用超能力帮助郭克松赚钱，也让郭克松逐渐开始忘记本性，甚至甩掉了青梅竹马的恋人向可人。这一切都被天日看在眼中，内心充满自责，对向可人也从可怜同情到转变为爱情。郭克松为了尽快达到自己发财的巅峰，将目光瞄准了张思敏，张思敏是富豪家的女儿，他希望能再次得到天日的帮助

天日发觉自己深爱向可人无法自拔，他以前也从来不知道什么叫感情，现如今即将到了快要离开的时候，他对向可人的感情只能保留在心中，可那种爱而不得的痛楚也撕扯着天日的心，如果他强行留在这里，必然会从大气层消失，是去是留心中彷徨不定。

Tianri (played by Chow Yun-fat) is a person with superpowers from an alien planet. By chance, he landed on the earth to find water, but there is no water source anywhere. , Seeing that he was about to die due to lack of water, fortunately he was rescued by Guo Kesong. From then on, in order to repay Guo Kesong's life-saving grace, Tianri used super powers to help Guo Kesong make money many times, and Guo Kesong gradually began to forget his nature, and even got rid of his childhood sweetheart Xiang Keren. All of this was seen by Tianri, and he was full of self-blame, and his sympathy for Xiang Keren changed from pity to love. In order to reach the pinnacle of his wealth as soon as possible, Guo Kesong set his sights on Zhang Simin, who is the daughter of a wealthy family, and he hoped to get help from Tianri again

Tianri finds that he loves Xiang Keren deeply and cannot extricate himself. When he left, he could only keep his feelings for Xiang Keren in his heart, but the pain of being unable to love also tore Tianri's heart. If he stayed here forcibly, he would definitely disappear from the atmosphere, whether to go or stay I feel uncertain.