When bratty 8-year-old Kevin McCallister (Macaulay Culkin) acts out the night before a family trip to Paris, his mother (Catherine O’Hara) makes him sleep in the attic. After the McCallisters mistakenly leave for the airport without Kevin, he awakens to an empty house and assumes his wish to have no family has come true. But his excitement sours when he realizes that two con men (Joe Pesci, Daniel Stern) plan to rob the McCallister residence and that he alone must protect the family home.
New York City policeman John McClane (Bruce Willis) is visiting his estranged wife (Bonnie Bedelia) and two daughters on Christmas Eve. He joins her at a holiday party in the headquarters of the Japanese-owned business she works for. But the festivities are interrupted by a group of terrorists who take over the exclusive high-rise, and everyone in it. Very soon McClane realizes that there’s no one to save the hostages — but him.
A gadget salesman is looking for a special gift for his son and finds one at a store in Chinatown. The shopkeeper is reluctant to sell him the “mogwai” but sells it to him with the warning to never expose him to bright light, water, or to feed him after midnight. All of this happens and the result is a gang of gremlins that decide to tear up the town on Christmas Eve.