Growing up on Staten Island, filmmakers Joshua Zeman and Barbara Brancaccio had often heard the legend of ‘Cropsey.’ For the kids in their neighborhood, Cropsey was the escaped mental patient who lived in the old abandoned Willowbrook Mental Institution, who would come out late at night and snatch children off the streets. Sometimes Cropsey had a hook for a hand, other times he wielded a bloody axe, but it didn’t matter, Cropsey was always out there, lurking in the shadows, waiting to get them. Later as teenagers, the filmmakers assumed Cropsey was just an urban legend: a cautionary tale used to keep them out of those abandoned buildings and stop them from doing all those things that teenagers like to do. That all changed in the summer of 1987 when a 12-year-old girl with Down syndrome, named Jennifer Schweiger, disappeared from their community. That was the summer all the kids from Staten Island discovered that their urban legend was real.