Plot

An over-the-hill hitman faces off against a younger clone of himself.

Retiring assassin, Henry Brogan finds himself pursued by a mysterious killer who can predict his every move. When he discovers that he is being hunted by a younger clone of himself, Henry needs to find out why he is being targeted and who the creator is.—bixy gello

Henry Brogan is an elite 51-year-old assassin who's ready to call it quits after completing his 72nd job. His plans get turned upside-down when he becomes the target of a mysterious operative who can seemingly predict his every move. To his horror, Brogan soon learns that the man who's trying to kill him is a younger, faster, cloned version of himself.—krmanirethnam

Henry Brogan (Will Smith), an aging former Marine Scout Sniper who now works as an assassin for the Defense Intelligence Agency (DIA), is sent on a mission to assassinate an anonymous terrorist aboard a bullet train. During the mission, Henry's spotter warns him of a young girl approaching the target, causing Henry to delay his shot until the last second, shooting the man in the neck despite aiming for his head. Disillusioned with killing, Henry retires from government service.

While adjusting to retirement, Henry meets boat rental manager Dani (Mary Elizabeth Winstead) and reconnects with an old friend, Jack (Douglas Hodge), who reveals that an informant named Yuri (Ilia Volok) told him that the man Henry killed was innocent; demanding proof, Henry has Jack arrange a meeting with Yuri. In retaliation for Henry knowing their deception, agency director Lassiter (Linda Emond) plans to kill him; Clay Varris (Clive Owen), head of a top-secret black operations unit code-named "GEMINI", requests permission to eliminate him but is denied.

Realizing Dani is a fellow agent sent to monitor him, Henry befriends her (fully knowing that Dani has been assigned to keep an eye on him). After his home is broken into by government agents, Henry calls his spotter, who is killed along with Jack and his mistress. Henry warns Dani about the attack, and they manage to kill the assassins sent after them, learning the agency wants them both dead.

Escaping to Colombia, Henry and Dani go to the home of Henry's former colleague Baron (Benedict Wong), and plan to meet with Yuri for further options. Meanwhile, Clay dispatches his top assassin to kill Henry. Fighting him off, Henry realizes the assassin bears an uncanny resemblance to himself as a young man, with a similar skill set. When the injured assassin arrives at a safe-house, he is revealed to be Clay's adopted "son" Junior. Although he is curious about his similarities to Henry, Junior is ordered to finish the job.

Henry is also troubled by his similarities to the assassin, whom Dani suggests might be his child despite Henry's denials. Testing DNA samples recovered from Junior, Dani discovers that his and Henry's DNA are identical - Junior is Henry's younger clone. Desperate for answers, Henry meets Yuri in Hungary, and learns of the cloning project and that the man he killed was one of the project's scientists. Having designed a method to produce clones devoid of pain or emotion, the scientist tried to leave the project and was killed upon being discovered.

To try to get Junior to turn away from Clay's intentions, Henry calls Lassiter (asking her to bring Dani back in), who agrees to send Junior to bring Dani safely back to the United States. Collecting Dani, Junior sets up a trap for Henry, but she warns him via a covert listening device hidden in her tooth. Ambushing the younger assassin, Henry explains to Junior that he is a clone, convincing him by revealing their similar traits that no one else could know. Escaping back to GEMINI, a heartbroken Junior confronts Clay, who claims that he must defeat Henry in order to surpass him.

Finding Henry after sneaking out of GEMINI, Junior allies with him to bring down Clay, while Henry urges Junior to quit in order to become someone better. Baron is killed in an ambush ordered by Clay, with Junior knocking Clay unconscious after a brief hand-to-hand fight.

After defeating a wave of GEMINI operatives, Henry, Dani, and Junior face another operative with special body armor who feels no pain or emotions. After shooting them repeatedly and along with several secondary explosions, they manage to kill it, they remove his helmet and he is discovered to be a younger clone, with all emotion and ability to feel pain removed. A defeated Clay tries to justify his actions towards Junior, who almost shoots him. Henry persuades Junior otherwise and kills Clay himself, having already lived with the heavy burden.

Assured that there are no more clones that were produced and that they are finally free from harm's way, Henry later meets with Junior, who has enrolled into college under the assumed identity of "Jackson Brogan" after Henry's mother's surname. Together, Henry and Dani plan Jackson's future.