“So Cold The River” (** out of four) was an elegant but empty horror thriller about a documentary filmmaker (Bethany Joy Lenz) who shows up at a resort town to investigate the town’s mysterious benefactor and uncovers (what else?) a sinister force lurking beneath the town’s picture-perfect landscape. Well-made, with sleek cinematography from Madeline Kate Kann and beautiful eerie locations, but it’s all window-dressing for a tired story that has been told far too many times before. “So Old The Plot” would have been a more apt title.