Scott Roper (Eddie Murphy) is the best hostage negotiator in San Francisco. His girlfriend Veronica "Ronnie" Tate (Carmen Ejogo) is a newspaper reporter.
While listening to a horse race on his car stereo, Scott is called downtown where a man named Earl (Donal Logue) is holding 17 hostages in a bank. Scott rescues the hostages by shooting Earl, though Earl's wound is non-fatal.
Scott is then assigned a partner â sharpshooter Kevin McCall (Michael Rapaport). That night, Scott takes his friend, Lieutenant Sam Baffert (Art Evans), to see a man named Michael Korda (Michael Wincott).
Scott waits downstairs while Sam is in Korda's apartment. Sam asks Korda about a man who deals in stolen jewellery, because Sam suspects that some of the dealer's jewels came from Korda, who is a professional jewel thief. Sam's visit with Korda ends with Korda violently stabbing Sam to death in an elevator. When Scott hears a woman in the building scream at the sight of Sam's body, Scott rushes to the elevator and witnesses Sam's corpse.
Scott wants to make Korda pay for killing Sam, but Captain Frank Solis (Denis Arndt) refuses to let Scott work the case, so Scott decides to work the case on his own.
Scott and Kevin later are called to a downtown jewellery store where hostages are being held. When Scott sees that Korda is the hostage taker, Korda grabs a hostage and leaves in a truck. Scott and Kevin use Captain Solis's car to chase Korda. Korda wrecks the truck, and boards a cable car, shoots the operator when he challenges Korda, the cable car accelerates to runaway speed, while Scott and Kevin chase the cable car. While up close, Scott jumps onto the cable car, leaving Kevin to drive Solis's car.
Scott and Kevin manage to stop the cable car, and they chase Korda into a parking garage, where Korda tries to run Scott over with a car. Scott and Kevin still manage to apprehend Korda.
During visitation at the jail with his cousin Clarence Teal (Paul Ben-Victor), Korda orders Teal to kill Ronnie as a way to seek revenge on Scott. Teal shows up at Ronnie's apartment and attacks Ronnie. Scott arrives just in time and chases Teal down the fire escape, and after a knife fight, Teal is hit and killed by a car. An angry Scott visits Korda in jail and warns him to stay away from Ronnie, showing him an autopsy picture of Teal, which enrages Korda.
On the next morning, Korda escapes from the jail. Soon after, he kidnaps Ronnie, luring Scott and McCall into a confrontation at an abandoned shipyard. Korda threatens to kill Ronnie by decapitating her on the cutting machine she is pinned to if Scott doesn't follow his instructions. While all of this is going on, McCall is situated atop a building outside with his sniper rifle watching the action. During the sequence, Korda prepares to run over Scott with his sports car. However, as he is charging towards Scott, Korda is shot at by McCall, causing him to miss Scott completely and crash through the front of the warehouse building. Scott then goes to free Ronnie from the cutting machine. After a shoot-out between Korda and McCall, the latter is shot once in the abdomen but survives. Scott then chases after Korda in Scott's truck, and after a lengthy battle over control of the truck, Scott leaps out of the way as Korda rams into a stack of explosive barrels and is killed in a massive explosion.
The movie ends with Scott and Ronnie relaxing on their vacation at a Tahitian beach resort.

Question: What mechanical object are Scott and Kevin able to stop?
Answer: A cable car