The video of this song shows a monster chasing a firefly at first. Eventually, the monster catches the firefly, he puts her in a cage. He realizes then that the firefly is sad, is losing her shine. He releases the firefly, and then he finds a lot of more fireflies. That's all I remember.
Edit: It was an indie/smooth-rock song, in English, with a male singer. I saw the video in YouTube, 2011-2012.