Awful stories of people living deep within the train and subway tunnels that snake through the infrastructure of major cities have long been the stuff of urban legend and horror movies. Web-footed, albino "mole people" who feed off of rats and human flesh scared audiences in C.H.U.D. and DEATH LINE, and even infiltrated an episode of The X-Files. But the sad truth is that an untold number of New York City's homeless really have made their way into the tunnels; 26-year-old Marc Singer was one such underground dweller, but he took a movie camera and some hand-held floodlights down with him. For two years, Singer lived with a community of homeless men and women who turned an old, garbage-strewn Amtrak tunnel into a thriving shantytown. Far from monsters, Singer found ordinary human beings who, living amid rats, garbage and perpetual darkness, found relative safety from the world above. People like middle-aged, former crackhead Ralph, who's been trying to keep himself and his carefully constructed shack clean; Dee, a crack smoker who hasn't been so lucky; and Tommy, a young Southern runaway from an abusive home, who's constructed both an elaborate home for himself and a kennel for his dogs. Singer doesn't offer any kind of introduction, so the fascinating circumstances surrounding his own adventure underground is never made explicit. What does become clear is, as one tunnel dweller puts it, "how much the human body can adjust to," as well as how hope and human decency can survive even in the most extreme circumstances. Singer's grainy, 16mm black-and-white photography lends the film the evocative aura of something that has been unearthed, while the spare, haunting soundtrack by DJ Shadow perfectly captures the sense of otherworldliness that pervades this remarkable film.