Growing up on Staten Island, filmmakers Joshua Zeman and Barbara Brancaccio had often heard the urban legend of "Cropsey." It was a cautionary tale invented to keep them out of the abandoned buildings that remained of the Willowbrook Mental Institution. Cropsey was supposedly an escaped patient who would come out late at night and snatch children off the streets—sometimes with a hook for a hand, other times with a bloody ax. But in 1987, Jennifer Schweiger, a 13-year-old with Down syndrome, disappeared from their community. For Zeman, Brancaccio, and the other kids of Staten Island, their urban legend became real.

Even as adults, this real-life boogeyman hasn't escaped the minds of the filmmakers. The eeriness of the mystery pulsates through the film as they journey into the underbelly of their borough to investigate not just Schweiger's disappearance but four other missing children linked to a shadowy drifter named Andre Rand. As more information and clues unravel, Zeman and Brancaccio become more immersed in shocking surprises and revelations. The reality they uncover in this uniquely hair-raising documentary is more terrifying than any urban legend.