We open in an interrogation room in Florida State Prison where we find the prisoner Courtland Gentry on one side of the table and CIA chief Donald Frizroy on the other. It’s 2003. Fitzroy offers to commute Courtland’s sentence if he agrees to work for the CIA. He explains that Courtland would be part of an elite unit known as the Sierra Program. Courtland is skeptical at first, but ultimately seems convinced that this opportunity is his only way out of prison.
Eighteen years later, we pick up with Courtland, now known by his codename only – Six. Six is on mission in Bangkok, Thailand where he’s meant to assassinate a rogue agent codenamed Dining Car. As a raucous party plays out around him, we find Six in a bespoke red suit, coolly observing his surroundings. He’s a far cry from the quippy, down-and-out prisoner from 2003.
Later, CIA operative Dani Miranda hands Six a water pistol with a key fob attached to it. Six uses it to enter a vacant room where he pulls back a construction tarp, revealing a case housing a high-tech audio-triangulating assault rifle. Over comms Six confirms that he’s arrived at the site in question. Denny Carmichael, CIA Center Chief, lays out the mission, elaborating that the target, codenamed Dining Car, is selling information that could compromise national security and that he needs to be eliminated before that transaction occurs. Denny expresses doubt to Suzanne Brewer, his deputy chief, about using a Sierra agent rather than someone in their circle of trust. But Suzanne confirms that Six was the closest agent in the vicinity of this transaction and that Six is historically good at what he does.
Meanwhile, Dining Car arrives in a procession of SUVs packed with his armed entourage. We follow him as he and his security detail make their way through the party and up to the floor where the Thai buyer is located. Six activates his high-tech rifle, tracking Dining Car’s movements using audio triangulation. He eventually acquires the target and Denny gives the go ahead to execute, but the sudden appearance of a child beside the Thai buyer gives Six pause. Denny commands Six to proceed despite the potential harm to the child, but Six ultimately chooses to abort the mission. Six claims the gun jams, vacates the room, and then pulls the fire alarm to prompt an evacuation of the building.
Immediately sensing something wrong, Dining Car and his security detail make their way out of the building. But as they traverse the now empty event space, Six starts to pick off Dining Car’s security guards one by one. Dani moves in to assist, taking on guards twice her size.
As Six kills each of Dining Car’s men, Dining Car throws one of his men through a glass window and leaps onto the fireworks barge below. Six follows suit. Dining Car reveals that he knows Six is Sierra Six and then goes on to reveal that he’s Sierra Four. As fireworks explode around them, the two engage in a brutal hand-to-hand fight, with Six eventually getting the upper hand and stabbing Sierra Four in the torso. Four says that Denny Carmichael can’t be trusted, then hands him the Thai coin hanging from around his neck, telling him that what’s in it will bring down the corrupt Carmichael.
Later, Carmichael contacts Six, who lies and says he doesn’t have the asset from Four. As he talks with Carmichael, Six opens the coin and finds a hard drive. Six goes on to review the contents of the hard drive at a computer cafe, discovering that the drive contains encrypted files on Carmichael that allude to his nefarious exploits. Dani calls Six, telling him that their exfil is happening shortly, but Six tells her he’s not coming with. Instead, Six proceeds to package and mail the asset to an unknown location.
From Bangkok, Six calls Donald Fitzroy, who’s currently located in Baku, Azerbaijan, where Fitzroy is set to attend an old friend’s funeral. Six tells Fitzroy that Carmichael is sideways and that Four gave him an asset that implicates Carmichael. Fitzroy offers to assist with Six’s extraction from Thailand, telling him to get to an airfield in Chiang Mai.
Back at Langley, Brewer tells Carmichael that Six blew off his exfil. Carmichael knows that Six has the asset, and tells Brewer that they need to bring in Lloyd Hansen. Brewer disagrees with that move, calling Lloyd a sociopath.
In Monaco, we find Lloyd Hansen in the middle of torturing someone with jumper cables when he gets a call from Carmichael. Carmichael wants Lloyd to go after Six to retrieve the stolen asset, using whatever means necessary. Carmichael cryptically adds that the Old Man doesn’t know about this yet, and that Brewer will be overseeing the operation. Lloyd suggests using Fitzroy to leverage someone Fitztory loves in order to get to Six.
Six arrives at the airfield in Chiang Mai, where he meets up with Fitzroy’s mercenaries. Meanwhile, Dani gets rerouted by Carmichael to Berlin.
At the funeral, Fitz encounters Lloyd, where the two of them exchange a barrage of biting banter. Lloyd wants to know where Six is, revealing that he’s kidnapped Fitztory’s niece Claire. With Claire in danger, Fitzroy is compelled to call the lead merc on the plane, commanding him to kill Six. Although outnumbered, Six fights back, exhibiting his extraordinary strength and agility under pressure. During the fight, an explosion blows open the side of the plane. As the plane plummets, Six jumps from the plane with a parachute, eventually catching up with another free-falling mercenary. Six fights and kills the mercenary as they both plummet to the ground, with Six getting a hold of the parachute just in time.
Landing in rural Turkey, Six calls Fitzroy to let him know that he survived the ambush. Fitzroy apologizes to Six, saying that he was leveraged with his niece. Six flashes to a memory of Claire in a hospital, establishing his strong emotional connection to the girl.
Lloyd takes over the call with Six, imploring him to come in. Six states the obvious – that he immediately doesn’t like Lloyd. After the call ends, Lloyd tells Fitz that he’s putting a hit on Six’s head, unleashing numerous international mercenary teams to track him down.
We pick up with Six stowed away on a train out of Turkey, scarfing down fast food. As he shoves the food into his mouth, we cut to Six two years earlier. We’re in the CIA station in London, more specifically, Margaret Cahill’s office. Cahill and Fitzroy inform Six that someone in the DC office leaked Fitzroy’s home address and now Six needs to provide protection for Fitzroy’s niece who’s currently living in Fitzroy’s house in Hong Kong. At one point, Cahill mentions that Denny Carmichael, for some curious reason, won’t provide agency protection. Fitzroy further explains that his brother and his brother’s wife died three years ago and on top of that, Claire was born with a heart condition. Claire received a pacemaker and has been in and out of the hospital ever since.
Now in Hong Kong, we meet Claire listening to music on vinyl records and taking pictures with a Polaroid camera. Claire meets Six, and their trademark banter is immediately established with Claire admonishing Six for chewing gum in the house.
Later, when Six walks outside to retrieve his suit jacket from a poolside chair, Claire asks Six about the tattoo on his arm. He matter-of-factly explains that he got it in prison and that it’s the name of a guy in Greek– the guy who the gods made push a rock up a hill.
That night Claire suddenly passes out in the house. Six rushes her to the hospital for treatment.
At the hospital, a doctor tells Six that there was a programming glitch with Claire’s pacemaker. He also mentions they can keep track of her pacemaker from anywhere in the world. Back at the Hong Kong House, Claire and Six share a moment over ice cream, with Claire saying that despite the hospital visit, it’s just another Thursday. They both conclude that Fitzroy is the closest family they have.
During their conversation, Six notices that the power to the security cameras around the house has cut out. He casually says good night to Claire and then conducts a perimeter check. Under the cover of darkness, the unnamed assassin infiltrates the house, but Six is ready for him. He immediately proceeds to neutralize the threat with his vastly superior fighting skills. Just Six knocks the assassin out, Claire comes out of her room to see if everything is okay. Six assures her that everything is fine, but Claire astutely observes Six pushing the man’s leg around the corner. It’s just another Thursday, Six says.
Back in the present day, we land in Vienna where Six retrieves a go-bag from a train station locker. From there, Six ends up at the apartment of Laszlo Sosa codenamed the Dry Cleaner. When Laszlo answers the door, Six tells him that he wants the “works”. Once inside, Six clarifies that he wants a whole new identity and papers. He also wants to get into the secure system of the company that monitors Claire’s pacemaker.
As Six cleans blood off hands in the bathroom, he has a quick flashback to his abusive father talking to him about taking a beating like a man. His father callously tells a young Six to fight through the fear, fight through the pain. Master that and you’ll never lose again.
As Six stands to have his passport photo taken, Laszlo releases a trap door beneath Six, who then plummets into a deep stone well. A plexiglass cover seals the well shut, with Laszlo then informing Six that there’s a huge bounty on his head.
At the CIA station in Berlin, Carmichael interrogates Miranda about her connection to Six. But she denies any knowledge of knowing about Six and what he did with the asset. In the meantime, back in the well, Six starts assembling something from the things he has in his go-bag.
On his private jet, Lloyd and his mercs get word that Six is in Vienna. In order to force an emergency landing in Vienna, Lloyd shoots the pilot in the leg. And back in the Berlin office, Carmichael explains to Miranda who the Gray Man are. Without Miranda’s cooperation, he recommends that Miranda be removed from her post. Right then he receives a text with Six’s location, which Miranda sees reflected in Carmichael’s glasses.
Lloyd and his mercs arrive at Laszlo’s apartment, where they find Laslzo casually knitting a sweater on the couch. When Laszlo asks where his money is, Lloyd kills him without a second thought. Just as the mercs approach the well, Six detonates his homemade explosive, blowing the top off the well, and killing the mercs in the process. Six quickly dispenses with several more mercs and then gets into a hand-to-hand fight with Lloyd. Lloyd pins Six against the wall when Six unpins a grenade and drops it between them, sending the two foes running for cover.
Outside, Lloyd catches up with Six and has him dead to rights when Lloyd gets tranq’d in the butt by Miranda. Miranda brings Six to her car and demands answers. When Six expresses reluctance to respond, Miranda shoots him with a tranq dart and shoves him into the trunk.
Now in a medieval castle in Croatia, Brewer reams out Lloyd for kidnapping Fitzroy and Claire, screaming that the CIA did not give you permission to do that. Fitzroy and Claire finally reunite at the castle.
Waking up after his tranq-induced snooze, Six reveals to Miranda that Sierra Four gave him an encrypted drive and that he sent it to Cahill in Prague.
Back at the Castle, a CIA Tech receives footage of Six mailing a package from Bangkok, and goes on to identify that the destination is a PO Box in Prague. Needing to find out who received the package, Lloyd does what he does best and tortures Fitzroy, pulling out his fingernails one by one.
In Prague, Six and Dani arrive at Cahill’s apartment while back in the castle, Lloyd rounds up the remaining merc teams to go to Prague.
A lifelong smoker, Cahill stoically informs Six that she has terminal cancer. But her illness didn’t stop Cahill from decrypting the drive, revealing that it contains intel on Carmichael’s “dirty laundry” aka his unsanctioned ops from around the world: assassinations, torture, bombings. Cahill goes on to explain that Carmichael is using the agency as his own personal hit squad, and that someone very powerful above Carmichael is pulling the strings.
Before they can further discuss this shocking revelation, Lloyd’s mercs converge on Cahill’s apartment and blow out the apartment’s windows, sending our heroes running for cover. Cahill gives the keys of her bug out car to Miranda and sends them through a trap door in the kitchen. Before Six can turn back, Cahill locks them in. The merc team finds Cahill in the kitchen casually smoking a cigarette. Before they can react, Cahill detonates the explosive, sacrificing herself to allow Six and Miranda to escape.
As soon as Six makes it outside, the apartment explodes, glass shattering everywhere. The Prague police attempt to detain Six, but he fights them off and escapes. But not for long. He’s eventually struck to the ground by a Prague police car. He is detained and handcuffed to a bench in the square near the Opera House.
Lloyd’s merc teams simultaneously descend on the square, launching a massive armed assault on Six and the Prague police, who can barely fight back. Pedestrians run for cover as a hail storm of bullets fly by in every direction. Six finally grabs a gun from a downed Prague police officer, and shoots the handcuff, freeing himself.
Six boards a tram, where he continues to fight off the merc teams by whatever means necessary. In Cahill’s bug out car, Miranda speeds alongside the tram, attempting to provide support. The tram is eventually blown off its tracks, and in a gravity-defying move, Six runs the length of the tram as it slams into a building’s pillars. Just as he’s about to get swallowed up by the exploding debris, Six jumps onto the hood of Miranda’s car.
Back in the castle, Brewer tells Hansen that this is the most spectacular failure in covert ops and what not to do in asset retrieval. Hansen directs his remaining mercenary Lone Wolf to retrieve the asset.
Six and Miranda enter a hospital reeling from the chaotic fallout of the recent attack. Six feigns an injury, which gives them enough cover to steal a hospital employee’s badge. They use it to enter the hospital so that they can access the location of Claire’s pacemaker. They discover that she’s being held in Croatia. Just as they’re about to leave, the Lone Wolf ambushes them, stabbing Six through the hand. Both Six and Miranda battle it out with the Lone Wolf, but he eventually gets the upper hand and acquires the asset. Six and Miranda chase him out of the hospital, but he successfully gets away.
Back at the CIA, Carmichael essentially threatens to throw Brewer under the bus if this op continues to go sideways. Meanwhile, Miranda shoots out an electrical transformer on the street so that the power goes out, offering them cover to break into a local veterinary hospital for supplies to treat Six’s stab wound and bullet wound. Six finally reveals to Miranda that he went to prison because he murdered his abusive father in order to protect his younger brother, but unfortunately ended up in jail rather than be lauded as a hero.
Back at the castle, Fitzroy assures Claire that Six is going to rescue them. At the same time, the Lone Wolf arrives at the castle with the hard drive, handing it off to Lloyd.
As Lloyd starts to celebrate, Six and Miranda arrive on the outskirts of the castle, immediately neutralizing two guards. Lloyd and Brewer start uploading the asset when the power suddenly goes out in the castle. Just then Miranda shoots down a helicopter with a rocket launcher.
As Miranda continues to attack the castle from the outside, Six infiltrates the castle, shooting his way through mercenaries until he arrives at the room where Fitzroy and Claire are being held. In the meantime, Miranda launches a rocket that blows up the command center.
Under fire, Six leads Fitzroy and Claire along the castle terrace. Lloyd eventually discovers that Claire and Fitzroy are missing and catches up with Six. In the midst of their escape, Fitzroy gets shot. Six and Claire are devastated, but Fitzroy, ever the self-sacrificing paternal figure, encourages Six to escape with Claire. Facing this impossible decision, Six and Claire jump from the terrace into the moat below. Lloyd finally catches up with the fatally wounded Fitzroy, who pulls the pin on a hand grenade, sending everyone running for cover.
Back in the remains of the command center, Miranda and the Lone Wolf fight it out for the asset. Once again, Miranda’s disproportionate strength is on display as she holds her own against the Lone Wolf. Meanwhile, Lloyd tracks down Six and Claire, who are crawling out of the moat.
The Lone Wolf is finally able to wrest the asset away from Miranda, but rather than claim it, he decides to return the asset to Miranda. He doesn’t care about the money anymore, saying that these are not honorable people.
Back on the castle grounds, Lloyd tackles Six to the ground. The two exchange fierce blows, each trying to get the upper hand. Claire grabs hold of a flare gun and shoots Lloyd in the back with it. Six then proceeds to shoot off two of Lloyd’s fingers, giving Six the opportunity to roll away and into the moat. Claire aims the flare gun at Lloyd, but he quickly overpowers her and drags her into the hedge maze.
Six pursues Claire into the maze while Miranda posts up in the castle with a sniper rifle. Inside the maze, Six catches up with Lloyd by a stone water fountain. Lloyd threatens to kill Claire, eventually firing the flare gun across Claire’s cheek.
After a heated standoff, Six tells Miranda to not take the shot on Lloyd, and then tosses his gun aside. Lloyd, in turn, releases Claire to Six. The two decide to engage one another in hand-to-hand combat. Claire pleads with Six not to fight Lloyd, but Six assures her that This is just another Thursday.
As the sun rises over the maze, Six and Hansen commence their hand-to-hand fight. At one point Lloyd retrieves a knife, stabbing Six multiple times until he’s able to overpower Six, forcing his head underwater. Submerged underwater, Six flashes to a memory of his abusive father similarly forcing Six (as a child) underwater.
The memory seems to give Six a burst of strength where he finally gets the upper hand on Lloyd, wrapping him in a chokehold. Six is on the verge of choking out Lloyd when Brewer emerges from the maze, burying two shots center mass into Lloyd. Bleeding out, Lloyd stumbles toward Brewer, where the two share a tacit moment of a newly shifted power dynamic. Lloyd finally collapses dead into the water.
As Six stands, Brewer shoots Six in the leg. Brewer explains that she went to Harvard with Carmichael and Lloyd and that their bromance connection got in her way. She then explains that Lloyd will take the fall for everything that happened and that Six will corroborate that story under threat of Brewer harming Claire. Brewer says that Six will likely return to prison, but if he behaves she’ll use him at times because he’s freakishly good at what he does.
Two weeks later, we’re in Washington DC where Six is in a military hospital under heavy guard. Meanwhile, at a government committee hearing, a government official exonerates Carmichael, Brewer and Miranda of all wrongdoing. After the hearing, Miranda threatens Carmichael should anything ever happen to Claire.
At a CIA safe house in Virginia, we find Claire being held against her will. Back at the military hospital, Brewer explains to Carmichael that as long as she has Claire, Six will do what she says. Carmichael threatens Brewer not to think too much for herself, implying that he knows that Brewer, not Six, killed Lloyd.
Brewer and Carmichael take the hospital elevator down to Six’s floor, where, once the doors open, they find dead guards littered across the hallway. They eventually discover that Six has escaped the hospital.
Back in Virginia, Claire finds a note in the record sleeve of Silver Bird. The note reads that the record should be played loudly. Claire covers her eyes as gunshots pop off around the house. A moment later, the door to Claire’s room opens. A triumphant Six stands in the doorway. Claire and Six embrace. The final shot tracks Six and Claire speeding down the driveway of the safe house, finally escaping the grasp of Carmichael, Brewer, and their CIA goons.