A man named [Smith](clive-owen) is seated on a bench, preparing to enjoy a carrot, when a woman in a vibrant yellow coat dashes past, being pursued by a man behind the wheel of an old black Camaro. Driven by instinct, Smith follows the chase, ultimately intervening to save the woman by driving the carrot straight through her assailant's head. But the struggle doesn’t end there, as a group of armed attackers arrives, prompting Smith to retaliate and take down several of them.
With the woman now in labor, they race into a nearby room where she gives birth. However, their escape is short-lived; they are ambushed yet again by a menacing figure, [Hertz](paul-giamatti), who is balding and wears glasses. Heartbreakingly, the woman is killed amidst the chaos, leaving Smith to flee with the newborn baby in his arms.
As Smith seeks refuge in a washroom, he engages in a tense battle with a stylish hitman, sparing his life before grabbing a bus ride. He ingeniously transforms his sock into a makeshift cap for the baby. In a moment of desperation, he leaves the infant on a park’s rotating ride, only for a well-meaning bystander to be shot by Hertz, who snipes from a distance. Smith acts quickly, rescuing the baby yet again.
His journey leads him to a church that turns out to function as a brothel, where he meets [DQ](monica-bellucci), a lactating wet nurse and sex worker. Smith offers her a substantial sum of $5000 to care for the baby, but she refuses. In a cruel twist, Hertz discovers the dead mother’s body and deduces the baby desperately needs milk, directing him to DQ's location. Hertz cruelly interrogates her for information on Smith, who returns in time to shoot Hertz and some of his henchmen, making a daring escape in a BMW. In his rage, Smith clashes with a Mercedes driver, launching a reckless pursuit.
Though Hertz survives and orders reinforcements, Smith finds himself trying to barter his change and a blood donation cheque for ammunition. Meanwhile, DQ finds herself earning cash in a more questionable manner. Smith safely takes both DQ and the baby to his loft, which he enters through a rat-activated door lock.
As Hertz catches up, his background as an FBI Forensic Behaviour Consultant becomes evident; he anticipates Smith’s next moves. Within the confines of his loft, Smith fashions a newspaper diaper and names the baby Oliver after the classic story. Music becomes a curious comfort for the baby, who calms when heavy metal plays and cries at political commentary.
Then, the calm shatters as dozens of attackers swarm in. DQ narrowly escapes down a dumbwaiter, while Smith and Oliver flee amidst a hail of bullets, cleverly using the baby’s diaper as a decoy. They end up in a local metal club where they uncover dark secrets linked to Oliver’s mother and a sinister operation involving babies.
Later, in a hotel room, Smith decides to wait while keeping watch on the news, reflecting DQ's somber memories of her own lost child. They share an intimate moment only to be interrupted by a swarm of armed assailants; Smith valiantly fights them off while still holding onto DQ.
Planning to transport DQ and Oliver to safety, Smith prepares for a confrontation at the Hammerson gun works. Anticipating trouble, the stage is set for an explosive showdown where Hertz confronts Smith, knowing personal details about him. Armed to the teeth, Smith employs clever traps to unleash fury on his enemies.
Realizing that the powerful Hammerson is involved in a much larger conspiracy, Smith connects the dots leading to Senator Rutledge, who needs the baby for a nefarious scheme tied to a firearm bill. After a thrilling street chase, Smith takes the fight to the sky, stealing a plane and demanding accountability from the Senator. In an act of revenge, he executes the Senator, igniting a chaotic aerial battle.
Wounded and desperate, Smith ultimately faces Hertz one last time in a brutal showdown, revealing tragic backstories and motivations. With cleverly planned traps, Smith outsmarts Hertz, leading to a dramatic conclusion. As the dust settles, Smith is left waiting for a green bus outside a church, filled with hope and the promise of reunion. Upon reuniting with Oliver and DQ, happiness is short-lived when chaos erupts yet again, but using quick wit and determination, Smith dispatches the armed robbers, all while still clutching a carrot.
End credits.
