A woman is kidnapped by a stranger on a routine flight. Threatened by the potential murder of her father, she is pulled into a plot to assist her captor in offing a politician.
After attending her grandmother's funeral in Dallas, Texas, Lisa Reisert (Rachel McAdams) takes a red-eye flight to Miami, Florida. While in the check-in line she meets Jackson Rippner (Cillian Murphy).
When boarding, Lisa discovers that Jackson is on the same flight and seated beside her. After take off, Rippner reveals that he is a terrorist operative working for a group who intends to assassinate theUnited States Deputy Secretary of Homeland Security Charles Keefe (Jack Scalia) and his family. Lisa is instrumental in their plans because of her job as Acting Manager at the Lux Atlantic Hotel where the Keefe family is staying. The assassination plan is to use a portable missile launcher from a boat in a nearby harbor and fire it at the hotel. In order for this to work, Rippner must force Lisa to make a phone call from the in-flight phone and order the hotel staff to change Keefe's reservation to a suite facing the harbor. If she refuses to cooperate, he will deploy a hitman to kill her father, Joe (Brian Cox), at his home in Miami.
Lisa attempts to find a way to keep both her father and Keefe safe. When she first places a call to the hotel, answered by her co-worker, Cynthia (Jayma Mays), the line goes dead midway through the conversation, and Lisa tries (unsuccessfully) to fool Rippner into thinking she is still ordering the room change. She then makes two unsuccessful tries to alert the other passengers to the danger. She first attempts to write a warning in the book, when the old lady from the check-in line comes to talk to her about it but Jackson, however, head-butts her unconscious after finding out. The second time is when she goes to the rest room, and writes a warning - in soap - on the mirror. When sitting in his seat on the plane, Jackson notices that the JetPhone In-Flight Telephone Service is in use. He heads over to the rest-room, and appears at the door just as Lisa is about to leave. He then sees the writing on the mirror, and forces Lisa back inside. When Lisa begs him not to kill her father, Jackson simply responds by telling her she should stop gambling with his life. He then notices a scar above Lisa's breast, and asks her if someone did that to her. When she tells him no, he then starts choking her - and shows his anger for her not being honest, when he was so honest to her. After letting her go, he starts using water-soaked paper-towels to wipe off the message on the mirror.
When the phone line comes back on, Lisa makes the phone call, and the hotel staff move the politician to the targeted suite. After the call, she asks Rippner to call off the man outside her father's house, but refuses until he has confirmation of the assassination. When she expresses concern that the hitman might get impatient and act before being called off, Rippner reassures her that he'll only act on Rippner's orders, that "he's a good dog, he only responds to the sound of his master's voice."
As the plane lands, Lisa confesses that the knife scar was from a violent rape she suffered two years ago, which she swore she would never let happen again. She then stabs Rippner in the throat with a pen (puncturing his windpipe and removing his voice), then takes his phone and flees the plane and terminal, narrowly escaping both Rippner and airport security. Once outside, she steals a nearby SUV. Noticing that the phone has a low-battery warning and could die at any time, she once again calls the hotel, alerting Cynthia to the danger. Cynthia pulls the fire alarm to evacuate the building and rushes to warn Keefe and his family, who are in the targeted suite. Cynthia, the Keefes and U.S. Secret Service agents manage to escape the room seconds before a Javelin missile hits.
Lisa, still driving, tries to call her father, but the cell phone's battery dies. She rushes to her father's house, arriving to find the hitman outside his door, and runs him down. Lisa finds her father inside, and he tells her that he has called the police. While Lisa phones the hotel to check in, Rippner arrives and knocks out her father. He chases her through the house with a knife and throws her down a flight of stairs. Lisa retrieves the dead hitman's gun from the floor and threatens Rippner with it. He attempts to escape, but Lisa shoots him before he can. He disarms and attacks her when, finally, Lisa's father shoots Rippner, incapacitating him as the police finally arrive.
Later at the hotel, Keefe and the Secret Service thank Lisa and Cynthia for saving him and his family from the assassination.Source: Wikipedia