Returned to her family, Liesl pines for her austere young man and for her brother. But from Vienna to the Bavarian forest, people are dying with mysterious marks on their lips and throat. The old laws cannot be broken. The Underground must have it due. Someone must die if spring is to return…

Plain, dutiful Liesl has given up her dreams for her family and longs only to make music, but once she played in the woods with the Goblin King. Her beautiful sister Käthe is engaged to be wed, but dreams of a life beyond the Bavarian forest. And if the Goblin King does not take a bride the world will fall into eternal winter. Which sister will he take? Which sister will he keep?