When an attack on the vulnerable United States infrastructure begins to shut down the entire nation over the Fourth of July weekend, New York City Detective McClane uses his old-school ways to frustrate the hi-tech hacker. It's the beginning of the holiday, but New York City Detective McClane isn't celebrating. He's had yet another argument with his college-age daughter Lucy, and received a crushingly routine assignment to bring in a young hacker, Matt Farrell, for questioning by the FBI..