For the kids, growing up on Staten Island, Cropsey was an 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. As teenagers, future filmmakers Joshua Zeman and Barbara Brancaccio had often heard the legend of Cropsey and assumed it was just an urban legend: a cautionary tale to keep them out of those abandoned buildings. That was until the summer of 1987 when a 13-year-old girl, named Jennifer Schweiger, disappeared from their community. As adults Joshua and Barbara return to Staten Island to investigate the mystery behind Jennifer and four other missing children. Embarking on a mysterious journey into the underbelly of their forgotten home town, the filmmakers uncover a reality that is more terrifying than any urban legend.