In a remote office building in Bogotá, Colombia, employees of Belko Industries find themselves trapped inside when the complex goes into lockdown mode without warning. A mysterious voice over the intercom informs them that they are part of a deadly social experiment where they must follow the instructions given or face lethal consequences. Initially, everyone believes it to be a prank, but the situation quickly turns dire when metal shutters seal off all exits, and the employees realize they're completely isolated from the outside world.

Panic sets in as the voice delivers increasingly horrifying ultimatums, demanding that a certain number of people must die within specified time limits, or more will be killed. Faced with these brutal directives, the employees’ morals and sanity are tested. Some band together, attempting to find a way out or resist the demands, while others succumb to fear and desperation, turning on each other in a bid for survival. Throughout the escalating chaos, alliances are formed and broken, revealing the darkest aspects of human nature and forcing everyone involved to confront what they are willing to do to stay alive.