Ezekiel Mannings, portrayed by Gary Oldman, is a billionaire contractor from New York who finds himself facing multiple corruption charges. His daughter, Alys Mannings, played by Calliope Jane Taylor, is well aware of her father's dubious dealings. In a tense meeting at a church, Ezekiel reassures Alys that everything will be just fine and advises her to consult Agent Bryant. However, shortly thereafter, he is apprehended by the NYPD right in the middle of the church.
Once under house arrest imposed by FBI agent Bryant, Ezekiel assigns various tasks to Alys to secure his freedom, as his communication becomes limited. He utilizes Alys's encrypted mobile phone to orchestrate his plans. Alys perceives her father as a visionary who constructed a formidable business empire from the ground up, believing that the investigation against him is merely a witch hunt.
Meanwhile, Nick Murch, played by Amit Shah, is a crucial witness based in London, set to testify against Ezekiel via a video link. Accompanied by Agent Simmonds from Interpol, Nick is taken to a secure room within the courthouse, oblivious to the sinister plot unfolding around him. The Courier, brought to life by Olga Kurylenko, is on her way to deliver a package, which unbeknownst to her, contains a cyanide delivery system intended to eliminate everyone in Nick's secure room.
As the situation escalates, Simmonds triggers the deadly device, but Nick narrowly escapes by locking himself in a bathroom. In a dramatic confrontation, Simmonds shoots the Courier, only to find out too late that she was protected by a ballistic vest. The Courier retaliates by disarming Simmonds and fleeing with Nick, who remains skeptical of her intentions despite her insistence that Simmonds was an inside agent.
The Courier, knowing that they cannot trust the authorities, opts to help Nick escape. After managing to retrieve her motorcycle from the building's basement, they find themselves cornered as Simmonds contacts Agent Roberts to inform him of the chaos. As Bryant declares an impending lockdown of the building, he believes he can eliminate any threats, including the Courier.
Despite the odds stacked against them, the Courier utilizes her training to stay beneath the radar, avoiding capture while she dispatches mercenaries as they hunt for Nick. Back in the United States, Ezekiel's defense team is pushing the judge to dismiss the case, even as they await news of the witness.
With each passing moment, Nick reveals crucial information to the Courier: he is the sole living witness to one of Ezekiel's murders. Armed with this knowledge, the Courier demonstrates her resourcefulness by making explosive diversions out of parked vehicles to outsmart the mercenaries. When one of them captures her, Nick finds the courage to intervene, helping her to regain control of the situation.
As the clock ticks down, Bryant enlists the help of a sniper, adding an even greater sense of urgency. The Courier shares her past experiences with Nick, revealing that she was once in the military and had lost her brother in combat. As they reach the rooftop, Nick is shot by the sniper and wounded, leading to a frantic retreat back inside the building.
With Bryant offering an enormous sum for Nick's capture, the Courier makes the bold move of cutting the building's power, utilizing her night vision helmet to take down Bryant’s mercenaries one by one. Despite succumbing to an injury herself, she remains relentless, ultimately battling Bryant and the sniper. In a fierce showdown, she fights to protect Nick and secures their escape.
Following a harrowing series of events, the Courier manages to get Nick to the hospital just as the FBI closes in on Ezekiel. The next day, Agent Roberts makes a shocking arrest, but he too holds a hidden agenda as he aims to eliminate the Courier, unaware that she is still very much in the game. Just as Roberts enters Nick's hospital room, the Courier corners him, setting the stage for a thrilling climax.
