Evelyn Salt, portrayed by Angelina Jolie, finds herself imprisoned and tortured in North Korea on accusations of being a U.S. spy. Her boyfriend, the esteemed arachnologist Mike Krause (played by August Diehl), garners so much media attention regarding Salt's captivity that the CIA, despite its stringent policies, is compelled to arrange a prisoner exchange. When Salt is welcomed back by her colleague, Ted Winter (Liev Schreiber), the two drive away, a moment of celebration turning bittersweet as Mike proposes to her, unaware of her true identity as a CIA operative.
Fast forward two years to Salt and Mike's wedding anniversary; the sudden arrival of Russian defector Oleg Vasilyevich Orlov (Daniel Olbrychski) disrupts their lives. During an intense interrogation, Salt interviews Orlov with the watchful eyes of her colleagues, including CIA counter-intelligence officer Darryl Peabody (Chiwetel Ejiofor). Orlov makes a shocking claim that on "Day X", a cadre of highly-trained Russian sleeper agents known as "KAs" will wreak havoc in the U.S. He recounts a chilling story of how these agents were recruited as children by the KGB, with the program dating back to the era of Lee Harvey Oswald. Orlov's claims culminate in a startling revelation that Agent "KA-12", tasked with assassinating Russian President Boris Matveyev (Olek Krupa) during the funeral of the American Vice President, is none other than Evelyn Salt herself.
As lie detectors confirm Orlov's assertions, chaos ensues when he executes two agents and makes a narrow escape, providing Salt with the chance to flee. Upon returning home, Salt discovers the horrific truth—Mike has been kidnapped. With her dog in tow, she swiftly gathers supplies, weapons, and one of Mike's precious spiders before setting out on her mission to rescue him.
The following day, amid the heavy security of the Vice President's funeral, Salt manages to infiltrate the event, donning a new look with dyed hair. In a chilling act that showcases her desperation and skill, she shoots President Matveyev, subsequently surrendering to Peabody rather than taking his life. The president is confirmed dead, but Salt's escape is not far behind as she makes her way to a barge where Orlov gathers other sleeper agents.
Through heart-pounding flashbacks, Salt reflects on her upbringing in the Soviet Union, where she was trained alongside other children. Her painful memories unfold as she recalls the tragic car accident that claimed the life of the real Evelyn Salt, allowing her to take on the identity of a deceased American girl. On the barge, Orlov menacingly welcomes her back and maliciously kills her husband before her eyes. Displaying no emotion, she earns his trust, only to plot her vengeance.
Indulging her resolve, Salt uncovers a plan involving KA Shnaider (Corey Stoll), who uses his position as a Czech NATO liaison to traverse her into the White House under a disguise. In a dramatic turn, Shnaider initiates a suicide attack, thrusting the President (Hunt Block) and Winter into an underground bunker for safety, and Salt capitalizes on the ensuing chaos to follow them.
Tensions escalate as the President learns about Russia's mobilization of nuclear weapons in retaliation for Matveyev's death. In a shocking twist, Winter betrays everyone in the bunker, revealing himself to be another KA and intent on launching a catastrophic strike against the Muslim world. Despite her attempts to reason with him, he discovers that Matveyev is alive, unveiling the elaborate ruse that Salt executed using spider venom. With the stakes higher than ever, a fierce struggle ensues between Salt and Winter as they fight for control of the nuclear launch protocols.
In an explosive climax, Salt manages to thwart the nuclear strikes before being restrained. As she is led out in chains, a dramatic confrontation with Winter unfolds, leading to his demise by her cunning maneuvering. During her helicopter ride towards interrogation, Peabody questions her motives. Salt passionately recounts her motivations, revealing that the orchestrated schemes against her were driven by Winter's sinister plan for revenge—spurring her promise to hunt the remaining KAs.
With evidence supporting her narrative surfacing, Peabody becomes convinced of her innocence. Ultimately, Salt is given a chance to escape, leaping from the helicopter into the depths of the Potomac River, ready to begin anew and reignite her pursuit of truth and justice.
