A very common saying: If you don't cherish something when losing it, you'll feel regret, and would then try to gain it back.

A young assistant falls helplessly in love with a shining star. One day, when the star came back with a movie script that has homosexual theme, he asked the young assistant to help him 'experience' the so-call love between two men. Throughout experiencing, the star hasn't recognized that he has already fallen for the young assistant. When the young assistant has already left, the star then finally realized his feelings.