One is the dream that will never comes into reality. Because it stay serenely inside the heart for long time, even no one know when it ends. That dream lives inside the soul forever and it is like a little happiness which will always blossom in sadness. They knew that it will always be only a dream, but they don't want to forget, they want to keep it, no matter what's going on. Because several parts of their life, still alive because of that dream.
That dream is a dream that will stay strongest, even hurt the deepest, but also the purest.