Julian Noble, portrayed by Pierce Brosnan, wakes up next to a hooker and curiously rummages through her belongings, discovering a bottle of purple nail varnish which he uses to paint his toenails. After disposing of some documents by burning them, Julian wanders into a Denver park, where he pretends to read a newspaper but is distracted by a sleek Porsche parked nearby. A young boy approaches him, commenting on the car and saying that his mother thinks Julian is attractive. In response, Julian gruffly remarks, > "I don't know anything about that car and I'm only interested in your mother if she lost 20 pounds and 30 years!" The boy scurries off just as a man enters the Porsche, and to Julian's indifference, the car erupts into flames.
Meanwhile, in another part of Denver, Danny Wright, played by Greg Kinnear, is startled awake at dawn by a violent storm. He quietly slips out of bed to prepare for a trip, hoping to avoid waking his wife, Bean, played by Hope Davis. As Bean awakens, they momentarily discuss their upcoming separation, and in a bid to cling to each other, they share an amorous moment before disaster strikes—a tree crashes through their roof, forcing them to leap for safety just in time.
At the airport, rain-soaked Danny rushes to catch a flight critical for his business venture, accompanied by his anxious partner. Coincidentally, Julian is also on the same flight, and he cheekily engages a ticket agent, declaring, "Couldn't be better. But more importantly how are you, Genevive?"
Upon reaching Mexico City, Julian encounters a mysterious man with a briefcase at their hotel. They briefly chat, with Julian inquiring about bullfights, stating, "My business is my pleasure." After the man departs, leaving his briefcase behind, Julian discovers it contains a sniper rifle and photographs of a target. At the same time, Danny and his partner leave the hotel, gearing up for a critical meeting, but the stress is palpable as they continue to worry about making a favorable impression.
Later, Julian attempts to engage a group of teenage girls at a shooting booth, only to have his confidence wane when he misses a shot. His boss, Mr. Randy, delivers the unsavory news that Julian's latest job has been rescheduled for that very day, with the sardonic reminder of his birthday—one that Julian seems to have completely forgotten.
Through a series of tumultuous events, Julian successfully carries out the assassination but returns to his hotel room feeling lost and isolated. He puts on a sombrero and briefly entertains the idea of visiting a brothel before finding himself back at the hotel bar, where he and Danny reluctantly strike up a conversation. While attempting to compliment him on his newfound business success after an unexpected job loss, Julian turns the chat sour with an inappropriate joke. Despite the initial tension, they gradually begin to bond after they share stories of personal loss and grief.
The next day, Julian delights Danny with an invitation to a bullfight, during which he tries to explain the culture surrounding the event. However, the mood shifts as Julian eventually confides that he is involved in something far more sinister, telling Danny that, "sometimes people need to be eliminated." Danny initially laughs it off, thinking it's a joke, but the gravity of Julian's true profession soon dawns on him as they venture into darker territory together.
As time passes, a bonding friendship develops between the two, culminating in Julian revealing his own vulnerabilities and regrets. When circumstances push him into a corner, he seeks Danny's help for a job he feels inherently unfit for. Together, they embark on a mission that tests both their limits and moral compasses, leading to thrilling and perilous situations in Arizona aimed at eliminating an imminent threat.
As they wrap up their harrowing experience and head back home, their newfound camaraderie evolves, with Julian acknowledging his connection to Danny and how the events have redefined their perspectives on life and friendship. The film culminates as Danny and Bean arrive at a place of healing, paved by Julian's tumultuous journey, leaving him able to move on, perhaps to Greece, searching for peace amidst the chaos he has endured.
