He steps off the train. He looks around expecting her to be there. She said she would meet him. It is why he came. She does not answer her phone. As the night approaches, he gets a text message, waits patiently for the next train back to where he started.
It starts quickly and unexpectedly. You do not know when it will start, why, or what it will bring. There are times when even after it is done, you cannot be certain what it was, what it did, what it meant. Often, though, you forget it before you have time to capture it. It is evanescent, an intense glimmer that can quickly fade to a void, as though it was never there. You wish you could capture it, but you know well that dreams act under their own rules.