Special tactics officer Rama prays, practices Silat, and bids goodbye to his father and wife who is pregnant with his child. He cryptically promises his father he’ll “bring him home.” Rama joins a heavily armed 20-man elite police squad, including officers Bowo, Dagu, Sergeant Jaka and Lieutenant Wahyu, for a raid on an apartment block in Jakarta’s slums. The team intends to eliminate crime lord Tama Riyadi – who, with his two lieutenants Andi and Mad Dog, owns the block letting criminals and junkies around the city rent rooms under his protection. Arriving undetected, the team sweeps the first floors and subdues various criminal tenants; they also temporarily detain an innocent, law-abiding tenant delivering medicine to his sick wife in apartment #726. Continuing to the sixth floor, the team is spotted by a young lookout, who passes on the message to another lookout just before he’s shot dead by Lt. Wahyu; the latter youth raises the alarm.
Tama calls reinforcements and the team is brutally attacked. Thugs snipe two officers guarding the perimeter, eliminate two more in the van, and ambush the officers patrolling the first five floors. Cutting the lights, Tama announces over the PA system that the police are trapped on the sixth-floor stairwell, and he will grant free permanent residence to those who kill the intruders. In the darkness, the remaining team members are ambushed by shooters from above, and almost completely wiped out. Prior to the gunfight, Lt. Wahyu confesses to Jaka he staged the mission so he can eliminate Tama – who’s in league with corrupt police officials, including himself. The mission is not officially sanctioned by police command; nobody at HQ knows their location and there is no hope for reinforcements.
The only remaining officers Rama, Bowo, Jaka, Wahyu and Dagu retreat to an empty apartment as they are cornered by more armed thugs. To create an escape route, Rama uses an axe to cut a hole in the wooden floor so the team can descend to the lower level. Dropping to the room below, the team struggles to fend off Tama’s horde of thugs and Officer Bowo is critically injured in the process. In a last-ditch effort to defend his team, Rama uses a stove propane tank to construct an improvised explosive device that successfully eliminates the invading henchmen, giving the officers a small window of time. Out of ammunition, and with more of Tama’s reinforcements approaching, the team splits into two groups: Jaka, Dagu and Lt. Wahyu retreat to the fifth floor, while Rama and a critically injured Bowo ascend back above in search of the law-abiding tenant they encountered earlier.
Fighting through a handful of goons on their way to apartment #726, Rama pleads with the tenant for help; despite his sick wife’s protest, Gofar reluctantly hides the officers in his apartment. Five machete-wielding thugs arrive and ransack the man’s home. The leader, noticing a refurbished wall, begins stabbing it, narrowly missing Rama, but fail to find them. After tending to Bowo’s wounds, Rama leaves him with the couple to search for Jaka’s group. Crossing paths with the machete gang he runs to the eighth floor but is cornered. He defeats the group, including their leader, who he uses to smash through a window and cushion a three-story plummet onto a fire escape below. Exhausted, he makes his way to the sixth floor before being grabbed by Andi, who had just murdered two of Tama’s men in the elevator. Andi is revealed to be his estranged brother, who Rama signed up for the mission to search for at the urging of their father. Rama refuses to leave the building without his comrades, and Andi refuses to abandon his auspicious criminal life, “Just because you see what I do as wrong doesn’t mean I can’t be good at it.” Rama parts to search for his surviving colleagues.
Mad Dog discovers Jaka and his group hiding on the fourth floor. As Lt. Wahyu runs off, Jaka instructs Dagu to “protect him,” while Jaka is left at Mad Dog’s gunpoint. Instead of shooting him, Mad Dog challenges Jaka to a hand-to-hand fight which he ultimately wins and proceeds to snap Jaka’s neck, killing him. Mad Dog meets up with Andi to report back to Tama in the surveillance room. Tama, having learned of Andi’s treachery, incapacitates Andi and hands him over to Mad Dog for torture and execution. Rama regroups with Dagu and Lt. Wahyu in apartment #403. They make their way up, fighting through a narcotics lab, as they head for Tama on the 15th floor. Along the way, Rama discovers the room where Mad Dog is torturing Andi, causing him to separate from Dagu and Wahyu. Mad Dog lets Rama free Andi, and fights both brothers. He initially has the upper hand, but the brothers prove to be a match when working together. Following an intense and grueling battle, Rama kills Mad Dog with Andi’s help.
Meanwhile, Lt. Wahyu and Dagu confront Tama after killing off his remaining henchman. However, Lt. Wahyu ends up betraying Dagu by shooting him in the face before taking Tama hostage, intending to use him as a shield to escape. When the duo encounter Rama and Andi as they’re going down stairs, Tama taunts Wahyu revealing that he had already been waiting for them before the raid began and Lt. Wahyu was set-up by his corrupt higher-ups; indicating that he will be killed regardless of escaping. In despair, Lt. Wahyu kills Tama and attempts suicide, only to find he has no ammunition left.
Andi uses his influence to allow Rama to leave with the injured Bowo and a detained Lt. Wahyu. Gofar, who protected Bowo, watches from a window grinning with relief. Andi also hands over emergency blackmail recordings Tama made of corrupt officials he dealt with, telling him to contact Officer Bunawar. Rama asks Andi to come home, but Andi refuses due to his acclimation to his criminal lifestyle. Andi asserts he can protect Rama in his role as a gang boss, but that Rama can’t do the same for him. As he turns around and walks back to the apartment block, the trio exit to an uncertain future.