John McClane is forced to team up with a young computer hacker, Matt Farrell, to stop a master cyber-terrorist called Thomas Gabriel, who wants to shut down the entire nations computer infrastructure in a mass cyber attack.

When the videotape of the murder of a congressman unknowingly ends up in the hands of labor lawyer and dedicated family man Robert Clayton Dean, he is framed for the murder. With the help of the mysterious Brill, Dean attempts to throw the NSA off his trail and prove his innocence.

John McClane is back and badder than ever, and this time he's working for Homeland Security. He calls on the services of a young hacker in his bid to stop a ring of Internet terrorists intent on taking control of America's computer infrastructure.

John McClane and a young hacker join forces to take down master cyber-terrorist Thomas Gabriel in Washington D.C.

The story of humble London businessman Quan (Chan), whose long-buried past erupts in a revenge-fueled vendetta when the only person left for him to love - his teenage daughter - is taken from him in a senseless act of politically-motivated terrorism. In his relentless search for the identity of the terrorists, Quan is forced into a cat- and-mouse conflict with a British government official (Brosnan), whose own past may hold clues to the identities of the elusive killers.