In a dystopian Detroit, crime and poverty have led to the creation of "Brick Mansions," a dangerous, walled-off section of the city where the police no longer venture. Within Brick Mansions, the community lives under the heavy-handed control of drug kingpin Tremaine Alexander, who rules with an iron fist and has the neighborhood under constant surveillance. The rest of Detroit regards the area as a lost cause, while its residents struggle to survive amidst the rampant crime and desperation.

Outside the walls, undercover cop Damien Collier is determined to battle corruption and avenge his father's death. By a twist of fate, his path crosses with Lino, a fearless resident and ex-convict with a personal vendetta against the drug lord after his girlfriend is kidnapped. Together, Damien and Lino form an unlikely partnership. Combining Damien's law enforcement prowess with Lino's intimate knowledge of the maze-like neighborhood and parkour skills, they delve deep into Brick Mansions on a high-stakes mission to dismantle Tremaine's empire from within, while attempting to thwart a sinister plot that could devastate the entire city.