This is the summary of the movie.
Standing at 3,500 feet (1,100 m) and 225 stories tall, high-level Chinese financier and entrepreneur Zhao Long Ji has financed the construction of the world's tallest skyscraper in Hong Kong, which they call "The Pearl". Although the construction nears completion on this super-skyscraper with all the floors already constructed, the construction process has not been without complications.
Halfway through the construction process, rival gangsters under the control of Kores Botha, an international terrorist with ties to many major crime syndicates, decide to use their control of construction crews working on the skyscraper to extort millions of dollars in shakedown payments for preventing a massive strike of construction workers, potentially halting its progress. Zhao agrees to the shakedown amounts, but not without carefully tracking and recording Botha's international money laundering scheme in his attempt to "legitimize" the funds he has extorted. Zhao believes that the memory card they have created containing the money laundering tracking information on Botha will provide them with insurance against any attempt by Botha to extort money from them a second time. Botha learns of the existence of the memory card and makes it a personal priority to retrieve the memory card in order to destroy it and the incriminating information it contains, because his bosses will kill him if he doesn’t.
Meanwhile, a former FBI Hostage Rescue Team leader and U.S. war veteran, Will Sawyer, now assesses security for skyscrapers. Although having one leg amputated from the knee down from a previous mission, he is fitted with a modern prosthetic leg, which keeps his full mobility. Sawyer is tasked with inspecting the Pearl, and Sawyer confirms to Zhao, security officers Sawyer’s friend and fellow ex-FBI agent Ben Gillespie and Ajani Okeke, and insurance agent Mr. Pierce, the building’s fire and security systems are secure, but he needs to inspect the offsite security center that controls the system. Zhao then hands Sawyer a tablet that gives full administrative access to The Pearl's computer systems that can only be unlocked by facial recognition.
While heading to the Offsite Security Center, a thief working for Botha attempted to steal the tablet from Sawyer but fails, resulting in Ben to reveal he is working with Botha so that he can ruin Sawyer out of jealousy, before attacking Sawyer to steal the tablet. Ben is mortally wounded, and warns Sawyer that Botha’s men will kill him for the tablet before he dies. Botha’s subordinate Xia steals the tablet, before infiltrating the security center and killing all the personnel there. Meanwhile, Botha and his men ignite the 96th floor of the building, triggering and activating the computer controlled advanced fire extinguishing hardware meticulously constructed throughout the skyscraper. A hacker at the Security Center then hacks The Pearl's security systems, locking out administrative access to The Pearl to Zhao and his team, as well as disabling all the fire extinguisher systems above the 95th floor, causing a growing impenetrable fire line, cutting off all rescue operations from below to assist the survivors on the upper floors. After doing so, Xia shoots the hacker. The local police, believing that Sawyer is involved, attempted to capture him. Sawyer, knowing that his family is trapped on the floors directly above the blazing fire, breaks free from the police. Inspector Wu sends a team of officers to capture Sawyer, as Wu wishes to question him. Sawyer climbs a crane and breaks into the building, escaping Wu’s team.
Zhao and Akeke send two security guards to rescue Sarah, Georgia, and Henry from the fire, but the guards are killed in an explosion that destroys the nearby elevator, forcing them to navigate through the fire to the top floors, having been told to by Sawyer in a phone call. Zhao and Akeke, believing that Sarah, Georgia and Henry are dead, decide to evacuate all remaining personnel on board a helicopter at Pierce's suggestion, only for Pierce to reveal it was a trap and that he works for Botha. Akeke and the other workers are killed by Botha’s men, but Zhao escapes and seals himself in his penthouse. As the family was heading up, Pierce, having been ordered to capture Sawyer’s family, attacks them, but Sawyer appeared in time to kill Pierce. They become partially separated in the chaos of the growing fire which is spreading to higher floors, but Sawyer manages to get Sarah and Henry to a partially functioning elevator. Sarah and Henry use the elevator for a free-fall escape with the plan to engage the emergency brakes to reach the ground safely. Upon reaching the ground floor, Sarah helps the police identify Botha as the ringleader. Sarah then explains to the police that she saw the terrorists carrying parachutes, which explained how the terrorists planned to escape from the building.
When Sawyer finally locates Georgia, she has been abducted by Botha who uses her to negotiate his own escape from Sawyer and force him to capture Zhao. Sawyer was then forced to scale outside the building to a wiring panel to disable the doors to the penthouse. After entering the penthouse, Sawyer informs Zhao of his predicament as Zhao reveals the reasons for Botha’s attack. They plan to rescue Georgia. Sarah accompanies Wu and several other police officers to the Offsite Security Center, where they engage in a shootout with Xia and Botha’s men. Most of Botha’s men are killed, while Sarah knocks Xia unconscious. Sawyer pretends to give Zhao to Botha, only for Zhao to distract him allowing Sawyer to rescue Georgia. Zhao, Sawyer, and Georgia escape into the top of the Pearl, where Botha and his remaining men follow them. Zhao and Sawyer kill Botha’s men, but Botha injures Zhao and takes Georgia hostage. Sawyer attacks Botha and pushes him off a ledge, where Botha is killed by his own grenade and rescues Georgia.
Meanwhile, Sarah finds the stolen tablet dropped from Xia and discovers that she can override the shutdown of the high-tech fire extinguishing capability built into the skyscraper by rebooting the computer system. The fire is rapidly brought under control, and a police helicopter rescues Sawyer, Georgia, and Zhao, who tells Sawyer he plans to rebuild the Pearl. Sawyer and Georgia reunite with Sarah and Henry, and the family leaves the premises.
