Because of the breakup, Steven dreams himself far away into an insect world. Here he feels happy, saved and loved. When he’s awake, the comparison between the real world and his dream world makes him ever more miserable. This leads him to seek out his dream world more and more. Soon it interferes with his life so much, he has to give up his dream world. The morning after his hard goodbye, a few fireflies flies trough his Window. He keeps them in a jar with air holes in the lid to keep even just a little of his dream world alive.
Link to music video: https://www.youtube.com/watch?v=psuRGfAaju4
Link to lyrics: http://www.azlyrics.com/lyrics/owlcity/fireflies.html