Taylor, a United States Marine Corps veteran, records their activities for a college class after they return to duty from a recent officer-involved shooting.

At a public disturbance call, Tre, a Bloods gang member, yells racial insults at Zavala, who responds by accepting a one-on-one fistfight.

The following night, the officers respond to a noise complaint at a house party, where Taylor and Zavala encounter Curbside Gang members "Big Evil" and "LaLa".

When ICE agents intervene, the officers learn that the house is tied to the Sinaloa Cartel and are strongly urged to stay clear due to possible reprisals.

Arriving on scene, they find her partner Van Hauser has been stabbed through the eye, and rescue Sook from being savagely beaten nearby; both survive but promptly retire.

The next day, the officers are called to perform a wellness check on an elderly woman, but in her house they discover large amounts of heroin, dismembered corpses, and a message from the cartel.

Unbeknownst to them, the ICE has eavesdropped on a cartel phone call ordering the two officers "green-lit" for assassination; Big Evil, LaLa, and others are tasked with killing them.

In a flashback to the day of the shooting, Zavala recounts to Taylor a humorous story from the first time he and his wife slept together, before the two receive a call from dispatch.

David Ayer, who wrote and directed End of Watch, grew up in South Central Los Angeles and has had numerous friends in the LAPD.

[9] In contrast to his previous works, Ayer wanted to focus on the friendship between Taylor and Zavala and "have all the cop stuff drop away and become secondary to the chemistry of these guys".

[15] Tactical training was also given to the other actors playing police officers, including David Harbour, America Ferrera, Cody Horn, and Frank Grillo.

The website's consensus states: "End of Watch has the energy, devotion to characters, and charismatic performances to overcome the familiar pitfalls of its genre and handheld format.

[29] Olly Richards, writing for Empire, gave the film four out of five stars and summarized it as "a collection of cop-movie clichés but presented with sufficient flair and strong performances that the ride is enough, even if it's on rails".

Peter Debruge of Variety wrote that "Like a knife in the eye, End of Watch cuts past the cliches of standard police procedurals" and praised Ayer for depicting the LAPD as "an honorable and efficient organization of people working together".

[33] In a review for The Globe and Mail, however, Rick Groen opined that the focus on "saintly" police officers was less interesting than Ayer's "trademark grit and authenticity".

"[32] The Los Angeles Times's Betsy Sharkey applauded the chemistry between the two lead actors, as well as their individual performances, writing, "As good as Gyllenhaal is in this, Peña nearly steals the show.

[38] On the other hand, Amy Biancolli of the San Francisco Chronicle felt that although the cinematography was inconsistent, "it's used to deepen its main characters" and "lends the film a lively intimacy".