It's a setting from Whitewolf publishers. It's a pen and paper RPG where you get to play changelings, that is to say normal everyday people who were taken by the Fae, Fair Folk, Sidhe etc. It's kind of a modern day fairy tale setting, where people who have escaped their supernatural kidnappers struggle to survive in a world that has literally forgotten them. The sourcebooks are a great source of inspiration and the game itself is a blast.