IDRIS ELBA NEVER CEASES TO AMAZE ME. HE DIRECTED THIS BEAUTIFUL VIDEO ABOUT LOST LOVE. HIS ACTING AS ALWAYS IS ON POINT.
If you guys haven't found out yet. There is a syndrome where one loses they're sight when it gets dark, like simply getting more blind than normal when it gets dark. So that explains why he was running after the sun. He didn't want to lose the light, because without it he will be blind. Also where we can asses that the light is also the presence of his loved ones, hence the name Lover of the light.