When a mission to recover a stolen suitcase bomb goes terribly wrong, CIA agent Kevin Pope meets his demise. Operating undercover as an antiquities dealer named Michael Turner, Pope's death leaves the agency in a desperate situation. In a surprising turn of events, they learn that Agent Pope had a twin brother, Jake Hayes, who was separated from him at birth due to their mother's tragic passing during childbirth. Hayes, who struggles to make ends meet by hustling chess games and scalping tickets, has been living a difficult life in Jersey City. Meanwhile, his girlfriend, Julie, grows increasingly impatient, prompting her decision to relocate to Seattle.
The CIA successfully persuades Hayes to step into his brother's shoes and undergo extensive training for a mission taking place in Prague, Czech Republic. However, his lack of sophistication disappoints Agent Oakes, who openly expresses his distrust. After some initial struggles, Hayes is moved into his brother's old apartment in Manhattan as part of an effort to bait the men responsible for Pope's death. During an attack, Hayes narrowly escapes unharmed, but the urgency of the mission drives him to seek guidance from his foster mother before Oakes encourages him to persevere.
Upon arriving in Prague, Hayes encounters the seller of the suitcase bomb, Adrik Vas, an ex-Russian Army Colonel with connections to the Russian Mafia. The plot thickens when Hayes meets his brother's ex-girlfriend, Nicole, leading to a complex interaction. Just as they begin to form a bond, an ambush by rival buyers disrupts their plans, and as Nicole uncovers the truth about Hayes' identity, she reassumes her assignment with CNN covering the Balkans.
Determined to see the mission through, Hayes teams up with Oakes to steal the arming codes and close the deal. But their plans derail when Vas' men betray him. In a turn of events, when the rival dealers, affiliated with a Greek terrorist organization, realize they cannot detonate the bomb due to the missing codes, they kidnap Hayes's girlfriend, Julie. In a desperate act of bravery, Hayes surrenders himself to the kidnappers in a bid to save her, allowing the terrorists to reclaim the codes and arm the bomb.
The clock races as the CIA scours the city to find Hayes and the bomb. After extracting information from one of the captured terrorists, they trace the bomb to Grand Central Station. With time running out, they locate the bomb and discover Andre, a key figure in the plot, who has started the countdown. In a moment of courage, Oakes saves Hayes from two terrorists, allowing him to confront the explosive threat. As Hayes attempts to enter the disarm codes, Andre takes Julie hostage. To buy time, Hayes feigns shooting Oakes, leading to a climactic showdown where they eliminate Andre and Hayes disarms the bomb just seconds before it could detonate.
In a poignant conclusion, Hayes pays his respects at the memorial for fallen agents, visiting his brother's grave. Eventually, during Hayes's wedding, Oakes approaches him with a startling reminder about a vengeful criminal escaped from prison. This revelation sends Hayes into a panic, as he learns that the criminal mistakenly believes he is still Kevin Pope. However, Oakes bursts into laughter, revealing that it was merely a prank, and he genuinely came to celebrate the special occasion.
