New York City police officer John McClane travels to Los Angeles to reconcile with his estranged wife, Holly, at her company's Christmas Eve party. Upon his arrival at the Nakatomi Plaza, where the party is being held, McClane is quickly thrust into a situation far beyond any typical domestic dispute. Before he has a chance to speak with Holly, a group of well-armed and professionally organized terrorists, led by the cold and calculating Hans Gruber, seize control of the high-rise. The group intends to carry out a meticulously planned heist under the guise of a political action, their ultimate goal being to steal $640 million in bearer bonds from the building's vault.

With the partygoers held hostage and the building locked down, McClane realizes he is the only person in a position to thwart the terrorists' plan. Unarmed and isolated from the authorities outside who have yet to grasp the gravity of the situation, he must rely on his wits and resourcefulness to disrupt the heist and save the hostages. Evading capture, McClane begins a deadly game of cat-and-mouse with Gruber and his henchmen, attempting to sabotage their efforts while keeping his identity hidden. His plight is complicated by the arrival of the LAPD and FBI, whose responses to the crisis are hampered by bureaucratic inefficiency and Gruber's cunning.