Louis Bloom (Jake Gyllenhaal) is a troubled young driver trying to make a living off thieving. He has already hit his rock bottom right from the beginning of the film. Luckily for him, he stumbles upon a bunch of Nightcrawlers who shoot late night crime incidents for TV channels. He tries to get some work with them but is brushed off nice and easy.
Desperate to make a living he decides to start his solo career and turn to one last steal. He steals a bike only to pawn it only to get a camcorder with a police radio. He scans it at night and hires an assistant to help him through the night. The assistant's only qualification is his phone with a GPS. Thus begins his journey into the L.A Crime journalism. As a night-crawler, the avenues for a good scoop of a worthy story are really few while he battles through competition and time.
Bloom soon makes his first big scoop that allows him to charge onto a veteran journalist Nina (Rene Russo) now serving as a news director. He has already outplayed Nina on a date night when he ruthlessly blackmailed her into more than just a professional relationship. It wouldn't be wrong to say that he outplays in her own game with the help of his below quality camera. His footage of a ruthless murder crime scene allows him to go by the name Video Production News.
Bloom now finds himself with an opportunity and a thirst to do more. Little does he know that the boundaries between good and evil, ethical and unethical, sanity and addiction would blur so fast that he would find himself crossing the line of an observer. Nina, on the other hand, is stuck with Bloom and his ever growing demands for the sake of her dwindling career. While Rick who is now catching up to Lou demands a raise at an opportune time.
Bloom quickly agreeing to his assistant's demand takes him along on a chase. They are chasing two murderers armed with a gun. He calls the cop at a restaurant informing them about the gun and starts capturing the shootout. Rick follows him into the chase and Bloom finally uses Rick as bait, not only to draw the killer out but also to get more footage.
One deed after another or rather one footage after another, Bloom manages to place himself in the heart of L.A night-crawling business and crime journalism.