Deep in the heart of Jakarta's slums lies an impenetrable derelict apartment building which became a safe house for the city's most dangerous murderers, drug addicts and gangsters. This rundown block has been considered untouchable by rivals of the notorious crime lord Tama Riyadi and even the police. It is also protected by two of Tama's henchmen; the smart, calculated Andi and the fiercely loyal "Mad Dog". Everything changes, however, when an elite team is tasked with raiding the building in order to take down Tama once and for all.
Cloaked under the cover of pre-dawn darkness and silence, devout Muslim, expectant father and rookie cop Rama and a 20 man SWAT team, led by Sergeant Jaka, arrive at the apartment building under the guidance of Lieutenant Wahyu. Wahyu criticizes Jaka for bringing along so many raw recruits, but Jaka promises to keep them as far back as possible. Before entering the complex, the team encounters a man from the 7th floor whose wife is ill, but he escapes their custody soon after entering the building. Starting from the ground floor and moving up, they slowly and tactfully infiltrate the apartment block until they reach the sixth floor. The team is spotted by a child who raises the alarm before he is shot and killed by Lt. Wahyu.
Tama, watching the police on CCTV, cuts the lights off and announces to the whole block that he will grant sanctuary to those who kill the SWAT team. Meanwhile, Sgt. Jaka learns that the mission was not sanctioned by the department, only by Lieutenant Wahyu, thus no reinforcements or rescue will come. Worse still, the SWAT van is disabled and the building is surrounded by snipers who will kill anyone trying to escape. After a lengthy battle across a darkened stairwell, the team retreats to a nearby apartment and attempt to break through to the floor below. In the ensuing battle, Alee is killed and Bowo is injured, to save him, Rama, with the help from Dagu, uses a grenade, gas canister and fridge as a makeshift bomb, killing everyone in the hallway.
The SWAT members that survived the ambush are: Sgt. Jaka, Lt. Wahyu, Bowo, Dagu and Rama. After recovering from the gas explosion, the team split into two groups: Jaka, Wahyu and Dagu on the 5th floor and Rama escorting a wounded Bowo to safety on the 7th floor. Meanwhile, Tama sends Andi and Mad Dog to join the hunt for the survivors. However, Andi kills his two escorts in an elevator for reasons yet to be explained.
Rama and Bowo go to the only place they know to be safe; room 726, belonging to the man they met earlier. Having narrowly avoided detection by a machete-wielding gang, Rama leaves Bowo there to recover and heads off to find the others, but is eventually spotted by the machete gang. He barely survives the attack and as he staggers along the hallway, he is pulled aside by a familiar face. Elsewhere, Jaka works out that Wahyu is being paid to get rid of Tama, not arrest him. But before Wahyu confesses his mission to kill Tama,the group are found by Mad Dog and his men. Mad Dog holds Jaka at gunpoint while his gang pursue Wahyu; Jaka orders Dagu to protect Wahyu and he does so. Mad Dog captures Jaka but rather than shooting him dead in cold blood (revealing that shooting enemies dead is not his best hobby), Mad Dog challenges Jaka to a hand to hand combat. They both fight in a hand to hand combat where Mad Dog apparently defeats Jaka before killing him by snapping neck.
Rama's 'rescuer' is revealed to be Andi, his estranged brother who chose to leave the family and left no trace of his whereabouts. It was only during the mission briefing that Rama even knew of his part in Tama's gang. He tries to persuade his brother to come home and tells him about his wife's pregnancy. But Andi isn't swayed and leaves Rama to wait in his apartment, while he meets up with Mad Dog, dragging the corpse of Jaka to be presented to Tama. But when reporting back to his boss, Andi's betrayal is discovered and Tama stabs him through the hand before turning him over to Mad Dog for torture (it's also suggested that he'll be used as bait for Rama).
Rama regroups with Wahyu and Dagu and assaults the drug lab further up in the building and then on to the 15th floor where Tama is located. Rama is separated when he finds his brother and Mad Dog, who allows Andi to be untied, so he can challenge them both. The three men engage in a lengthy brawl, with Mad Dog easily holding his ground. Meanwhile Wahyu steals the gun of one of Tama's goons and kills him and two other goons before holding Tama at gunpoint, Tama is arrested but he is surprised when Wahyu betrays Dagu and kills him in cold blood, Wahyu then takes Tama hostage in order to claim his escape. In the battle, Mad Dog defeats Andi and injures Rama, but before he can kill him, Andi stabs Mad Dog with a sharp object but still, Mad Dog stays strong before Rama finally overpowers him and slashes his throat with the sharp object stuck to his throat, finally killing him.
Together, Rama and Andi catch up with Wahyu, who tries to kill them too, making Rama realize that Dagu didn't make it. Tama gloats to Wahyu about his situation and explains that the lieutenant is actually the one who's been set up to be killed. Just then, Tama begins to mention Reza, he reveals that Reza betrayed the lieutenant by having him set up by his corrupt higher ups before Tama reveals he had paid off the right people to ensure his own survival. Meaning that even though that Wahyu does survive and escape here, he will be killed later (which turns out to be true in the sequel). Panicked and feeling threatened enough, Wahyu ends this by killing Tama with a gunshot but his efforts to commit suicide fail because his gun is out of bullets.
In the aftermath, Wahyu is arrested, Rama reunites with Bowo and Andi orders the building's residents to stand down and provides Rama with information on all the corrupt cops, thanks to recordings that the extremely paranoid Tama had in his possession; including numerous of his blackmail recordings on corrupt officers taking ribes. Andi then walks Rama, Bowo and Wahyu to the front gate, but declines Rama's offer to join them. The cops head away and Andi returns to an uncertain future as the film ends.