12 years after after John McClane(Bruce Willis) stopped Simon Gruber, he's back with a problem which is going to be more difficult and personal than ever before. An organization of Internet-based terrorist led by Thomas Gabriel(Timothy Olyphant). They are taking control of everything in America from their computers and slowly taking over the country. Accompanied by Matthew Farrell(Justin Long), one of the hackers who accidentally assisted the villains in setting up the system, McClane must both find Gabriel and help prevent him from taking over America completely. Gabriel knows McClane's on his way, and will make it as personal as possible, which means involving McClane's daughter, Lucy(Mary Elizabeth Winstead).