Friday, August 15, 1975, began as a typical summer day in Marple Township. Young children played with their friends as adults prepared for work and planned for their vacations at the Jersey Shore. That all changed in the hours before noon, when Gretchen Harrington, the eight-year-old daughter of a Presbyterian minister and his wife, was kidnapped while walking to a vacation Bible school near her home. Her body was found by a jogger in a state park nearly two months later. The crime forever affected Gretchen's contemporaries and their parents in the region, many of whom chose to live in suburban Marple Township because they considered it a safe refuge from a crime-ridden Philadelphia. With rare access to police files, journalists Mike Mathis and Joanna Falcone Sullivan examine the kidnapping, murder and the nearly five-decade-long investigation in what is tragically still a cold case.