Plot
Lieutenant Danny Roman, a top hostage negotiator for the Chicago Police Department's east precinct, is told by his partner, Nate Roenick, that according to an informant whom he refuses to name, members of their own unit are embezzling large amounts of money from the department's disability fund, of which Roman is a board member. Roenick tells Roman that his informant hasn't told Internal Affairs because he thinks they might be involved as well. Later, Roman goes to meet Roenick but finds him dead, shot in the head. A squad car arrives on the scene within seconds, with Roman considered a prime suspect.
Matters become worse for Roman when IAD inspector Terence Niebaum, whom Roenick's informant suspected of involvement in the embezzlement, is assigned to investigate the murder. After the gun that killed Roenick, which is found in the lake next to his car, is linked to a case Roman had worked on, Niebaum and other investigators search the Roman household and discover papers for an offshore bank account with a deposit equal to one of the amounts of money embezzled. Roman is forced to surrender his gun and badge, and his colleagues are skeptical of his protestations of innocence. With embezzlement and homicide charges pending, Roman storms into Niebaum's office to confront him. When the inspector refuses to cooperate, Roman takes Niebaum, his administrative assistant Maggie, Roman's commander and friend Grant Frost, and con man Rudy Timmons as hostages.
With the building evacuated and placed under siege by his own CPD unit and the FBI, Roman issues his conditions: He wants his badge back, the location of Roenick's informant and killer, a department funeral if he dies, and the presence of Lieutenant Chris Sabian, the city's other top negotiator. Roman believes he can trust Sabian because he talks for as long as possible, sees tactical action as a last resort, and, being from the CPD's west precinct, is eliminated as a suspect in the disability fund scheme. Sabian clashes with Roman's precinct, particularly commander Adam Beck, but is given temporary command of the unit after they hastily attempt a breach that backfires, resulting in SWAT officers Scott and Markus becoming hostages, with Scott apparently getting killed.
Roman trades Frost to Sabian in exchange for getting the building's electricity restored, which had been turned off after the hostage execution. With help from Rudy and Maggie, Roman accesses Niebaum's computer and discovers the scheme: Corrupt officers submitted false disability claims that were processed by an unknown insider on the disability fund's board. He also discovers recordings of wiretaps, including a conversation between Roenick and his widow that suggests he was going to meet his informant before he was killed. Sabian, using the information Roman gave him, claims to have located Roenick's informant in a bid to get Roman to release the hostages. Roman realizes Sabian is bluffing when Niebaum's files reveal that Roenick himself was the IAD informant.
When Roman threatens to expose Niebaum in his office's shattered window, leaving him vulnerable to sniper fire, Niebaum admits that Roenick gave him wiretaps, implicating three of their squadmates in the embezzlement scheme: Hellman, Allen, and Argento; when Niebaum confronted the guilty officers, he received a bribe from them to cover up their crimes; the guilty officers attempted to bribe Roenick, but he refused to take the money, resulting in his murder. Niebaum says he doesn't know who the ringleader is, but that he has safely hidden the taps corroborating the three officers' guilt. Meanwhile, the same corrupt officers have secretly entered the room via the air vents, under the pretext of being part of a team to take Roman out in case he starts killing the hostages. Upon hearing Niebaum's confession, they open fire and murder him before he can reveal where he has hidden the wiretaps. Roman single-handedly fends them and the rest of his squad off, using the flashbangs he seized from Markus and Scott in the previous failed breach.
Believing that Sabian and the police can't resolve the situation, the FBI assume jurisdiction over the operation, cease negotiations, relieve Sabian of his command, and order a full breach. As Roman prepares for his eventual arrest, Maggie tells him that Niebaum also worked from his house and could have kept Roenick's wiretaps there. Sabian re-enters the building and warns Roman about the breach, and the latter reveals that Scott is still alive and gagged with duct tape. Sabian begins to believe in Roman's innocence and gives him a chance to prove his case. While the FBI and SWAT teams raid the building and rescue the hostages, Roman disguises himself as a SWAT member and escapes through the vents.
The two negotiators proceed to Niebaum's house, but are unable to locate the wiretaps. The police arrive and the corrupt officers enter the house, but they back off as Frost enters and tries to talk Roman down. Sabian observes Frost discreetly locking the front door and taking one of the loaded guns and realizes that he is the ringleader of the conspiracy, the insider on the disability fund's board and Roenick's killer. In front of Frost, Sabian seemingly kills Roman, and offers to destroy the evidence on floppy disks they have uncovered in return for a cut of Frost's take. Frost agrees and effectively makes a full admission to his and the three other officers' crimes before crushing the floppy disks and shooting Niebaum's computer. When Frost exits the house, he discovers that Sabian only wounded Roman, who used a police radio microphone to broadcast Frost's entire confession to the police surrounding the area. Humiliated, Frost attempts to commit suicide, but is shot in the shoulder by Beck and arrested along with the other corrupt officers. As Roman is loaded into an ambulance with his wife, Sabian gives his badge to him and departs.
