“Ghosts of Christmas Past” Contrary to popular belief, the current zombie outbreak is not the first time a shadow fell across Riverdale and its citizens. As the survivors hunker down in a hotel to wait out a snowstorm, Hiram Lodge and Mary Andrews relive the darkest chapter of their town’s history. Ten years ago, the adults of Riverdale struck a terrible bargain with the witches of Greendale, setting the stage for the present-day apocalypse.FOR TEEN+ READERS.