The metro's secret passageways throb with illicit desire, as anonymous figures meet in the shadows for quick, passionate trysts. A redhead, her hair disheveled and her makeup running, is bent over, her skirt hiked up, as a stranger pounds into her from behind. The screeching of the trains overhead masks their moans, the rhythmic clacking of wheels on tracks setting the pace for their frantic coupling. In another corner, a couple, their faces obscured by darkness, entwine, their bodies slick with sweat, lost in their own world of forbidden pleasure.