Another theme might be about endings and new beginnings. Just as dusk is the transition between day and night, the story could be about characters experiencing the end of one phase of their lives and the start of something new. For example, a character might be ending a long - held job at dusk and starting a new adventure the next day. Also, it could be about the mystery that often comes with the fading light of dusk. Things are not as clear as in the day, and this could mirror the mystery in the characters' lives.