Former L.A. SWAT officer Jeff Talley is a hostage negotiator in Los Angeles. One day, Talley negotiates with a man who has taken his wife and son hostage after learning his wife was cheating on him. Shortly after Talley denies a SWAT commander's request to give snipers the order to open fire, the despondent man kills his wife, son, and himself. Traumatized, Talley moves with his family and becomes police chief in Bristo Camino, a fictional suburban hamlet in nearby Ventura County.
A year later, Talley finds himself in another hostage situation. Two troubled teenaged brothers, Dennis and Kevin Kelly, and a sociopathic accomplice, Marshall "Mars" Krupcheck, all very well-armed, take Walter Smith and his two children, Jennifer and Tommy, hostage in the Smith home after a failed robbery attempt. Dennis had told his younger brother to wait in the car, not anticipating the siege to come, but Kevin refused.
A female police officer, Carol Flores, responds after Tommy turns on the silent alarm. She is shot twice by Mars after being informed by dispatch that the red truck (parked by the hostage takers in front of the house) is a stolen vehicle just before Talley arrives. She dies in front of him. Traumatized and unwilling to put himself through another tragedy, Talley hands authority over to the county sheriff and leaves.
Smith had been laundering money for a mysterious right-wing militia and mafia syndicate through offshore shell corporations. He was preparing to turn over a batch of important encrypted files recorded on a DVD when he was taken hostage. To prevent the incriminating evidence from being discovered, the syndicate orders a ruthless operative, known as "the Watchman", to kidnap Talley's wife and daughter. Talley is instructed by "the Watchman", to return to the hostage scene, regain authority, and stall for time until the organization can launch its own attack against Smith's house. Otherwise, Talley's wife and daughter will be murdered.
Dennis forces Kevin and Mars to tie up the children, while he knocks out Smith and finds a small fortune in cash, money which the syndicate had paid Smith. In an attempt to end the standoff and secure the DVDs himself, Talley meets with Dennis and agrees to provide a helicopter in exchange for half of the money.
When the helicopter arrives, Dennis and Kevin bring the money to Talley and prepare to leave, but Mars refuses to leave without Jennifer, with whom he has become infatuated. Talley says the helicopter will only carry three passengers and insists Jennifer stay behind, but the deal breaks down and the boys and Jennifer return to the house. Talley learns that Mars is a sociopath who could turn on the hostages and his own accomplices at any moment. Mars does, in fact, kill Kevin, just as Kevin is about to release the children. Mars then kills Dennis.
The syndicate sends fake FBI agents to recover the DVD and they storm the house; Talley is instructed to not go near the house. Jennifer manages to stab Mars, but not fatally, and locks herself and Tommy in the panic room.
