Mallory Kane (Gina Carano) enters a diner in Upstate New York and waits. A car arrives and Aaron (Channing Tatum) joins her. After a short conversation about their employer, Aaron orders Mallory to get in his car. She refuses, and they fight, with Aaron nearly capturing Mallory before the intervention of Scott (Michael Angarano), a customer in the diner, allows Mallory to break Aaron's arm, knock him unconscious, and escape with Scott in Scott's car.
Mallory tells Scott that both she and Aaron are contractors with a private firm employed by the American government for covert operation assignments. One week before, at a meeting among government agent Coblenz (Michael Douglas), his contact, Rodrigo (Antonio Banderas), and Mallory's ex-boyfriend and the firm's director Kenneth (Ewan McGregor), the firm was hired to rescue Jiang (Anthony Brandon Wong), who is being held in Barcelona. Mallory and her team, which includes Aaron, succeed in rescuing Jiang and delivering him to Rodrigo.
Shortly thereafter, Mallory is approached by Kenneth, who insists she undertake what he claims is an easy assignment: pose as the wife of British agent Paul (Michael Fassbender) during a mission in Dublin. Mallory agrees and accompanies Paul to a party at Russborough House, where they meet with his contact, Studer (Mathieu Kassovitz). Paul meets with Studer again as Mallory watches from afar. She sees Paul go into a barn, and after he leaves she enters it to find Jiang dead, clutching in his hand a brooch which Kenneth required her to wear as a recognition signal for her initial contact with Paul.
Mallory realizes she has been set up and returns to her hotel room, where she is attacked by Paul. They fight, Mallory gets the upper hand and eventually shoots Paul dead. Mallory calls Kenneth from Paul's phone and Kenneth reveals that he's aware of the set-up before realizing it's Mallory he's speaking to. As Mallory leaves her hotel, she evades what are presumably Kenneth's agents tailing her, but a SWAT team appears and tries to arrest her. She escapes after a chase, and manages to enter the United States and reach the diner, where she meets Scott.
Mallory calls Rodrigo from Dublin and asks him whether it was he or Kenneth who set her up, then hangs up. This prompts Rodrigo to call Coblenz, who then calls Mallory. Coblenz tells Mallory that he has had suspicions about Kenneth for some time. Coblenz then contacts Kenneth and tells him to inform Mallory's father, John Kane (Bill Paxton), (who already knows of his daughter's occupation), of her crimes. Meanwhile, on the road, Mallory and Scott are chased by the police and hit a tree after a deer runs into Scott's car. They are both arrested, but soon the convoy is ambushed by assassins posing as federal agents sent by Kenneth. Mallory escapes, kills one of the assassins, and releases Scott. She gives him a number to call for protection and leaves to meet with her father.
Mallory reaches her father's house in New Mexico before Kenneth, Aaron, and two additional men arrive, posing as the police, to interrogate John on his daughter's whereabouts. Aaron starts to realize, after receiving a photograph on his phone of Jiang lying dead, that Mallory might have been set up. He tries to press Kenneth for the truth, but Kenneth shoots him in the abdomen and escapes as Mallory takes out his men. Aaron apologizes to Mallory, and eventually dies in her arms of excessive blood loss.
The following day Mallory meets with Coblenz, who reveals that he ordered Kenneth to contact Mallory's father so she could kill him there. Mallory asks Coblenz to fix things with Scott, which he promises to do. Coblenz also informs Mallory of Kenneth's location. Before Mallory leaves, Coblenz offers her a government job but she replies only that she'll let him know, after she finds Kenneth.
In Mexico, Mallory confronts Kenneth at the beach and they fight. Kenneth tries to escape, but gets his foot twisted and jammed between two rocks. Kenneth reveals that Jiang was a journalist who had written a series of articles exposing Studer's crimes. Knowing that Mallory planned to leave his firm, Kenneth arranged for her to rescue Jiang and deliver him to Rodrigo, who then delivered him to Studer, who killed him. Kenneth then framed Mallory, planning to cut all ties that could lead to him by convincing Paul that Mallory was a double agent whom he should kill. With all crimes being blamed on Mallory, Paul would eventually run free claiming to have killed her in self-defense. Disgusted, Mallory leaves Kenneth to drown in the incoming tide for his betrayal.
A few days later, Mallory locates Rodrigo, who is enjoying a "retirement" in a hotel in Majorca. She confronts him in his room, ready to eliminate the last remaining link of the conspiracy against her.