Ed Zimmer is a lonely, New York City tour guide who leads a double life. By day, he points out famous landmarks to wide eyed tourists. But when Ed returns home at night, he is plagued by nightmares; disturbing visions of a child abduction which seem too real to be a figment of his imagination. Tortured by these thoughts, Ed ventures out into the gritty underbelly of New York City to investigate. After a dangerous encounter with a real life killer, Ed becomes obsessed with avenging the innocent and begins hunting down the murderers who haunt him in his sleep. Meanwhile, Ed attempts to maintain a romantic relationship with a Russian tourist named Lucya, who doesn't know about his dark secret. As the vigilante killings escalate, Ed's unhinged behavior makes Lucya fear that he is descending into madness.