Caught in the act of stealing from a construction site in Los Angeles, Louis "Lou" Bloom (Jake Gyllenhaal) assaults a security guard and makes off with his watch. Desperate for a job after trying to sell the stolen materials at a scrap yard, Bloom is turned away by the foreman, who refuses to employ a thief. His life takes a turn when he witnesses a freelance film crew at the scene of a car crash, led by the seasoned cameraman Joe Loder (Bill Paxton). Inspired, Lou steals a racing bicycle to trade for a camcorder and radio scanner, stepping into the world of professional stringing.
Bloom wastes no time: he films the aftermath of a carjacking, unflinchingly capturing the victim's death as a means to outdo Loder, leading to a rivalry. He presents his footage to local TV station morning news director Nina Romina (Rene Russo), who buys it and pushes him to focus on violent incidents in wealthy areas to attract viewership. Eager to make money, Lou brings on board an assistant, Rick Carey (Riz Ahmed), a financially struggling young man.
To enhance his footage, Lou engages in disturbing practices, such as manipulating crime scenes to secure more dramatic shots. Yet, Loder consistently beats him to crucial stories, aided by superior equipment. As Bloom’s reputation grows, he invest in upgraded gear, trading his old car for a shiny new Dodge Challenger. His relationship with Romina takes a turn for the manipulative when he threatens to jeopardize their professional bond if she doesn’t become intimate with him, cognizant of the leverage his footage provides her job security.
Bloom's burgeoning career hits a snag when he turns down a business opportunity with Loder, only to see Loder scoop an important plane crash story. Frustrated, Nina reprimands Bloom, demanding he deliver footage that will captivate audiences. In a desperate move, Bloom sabotages Loder's vehicle, resulting in a severe crash.
As the plot thickens, Bloom rushes to capture footage of a brutal home invasion in an upscale neighborhood before the authorities arrive. He films the criminals and the aftermath, putting ethical boundaries to the test. Romina, eager to feature the story, offers him not only financial compensation but also public credit for his work. However, Bloom is already on thin ice with law enforcement, as they start to scrutinize his operations.
Navigating the dangerous waters of journalism, Bloom provides the police with an edited version of the footage, conveniently omitting key evidence that could identify the perpetrators. Meanwhile, he and Carey stake out the suspected criminals, leading to a chaotic confrontation where Bloom captures everything on camera—even the tragic moment when Carey is shot while trying to document an escape attempt.
In a shocking twist, Bloom focuses the camera on a dying Carey, revealing just how far he is willing to go for success, stating he cannot collaborate with someone he doesn't trust. With Romina captivated by his footage, she overlooks the underlying truth of the stories they tell, enhancing their allure for viewers. As tensions rise, Bloom cleverly manipulates the situation to expand his operation, investing in more vans and recruiting interns, all while dodging the police as they grow increasingly suspicious of his methods.
