After getting into a fight with his older brother Buzz McCallister because he purposely ate Kevin's cheese pizza, Kevin is sent to the third floor of the house by his mother Kate. The next morning as the family prepares to leave, Kevin is still sleeping. His cousin Heather mistakes Mitch Murphy, Kevin's neighbor who was just about to leave for vacation too as Kevin.
Marv & Harry, two bandits, start robbing houses in his neighborhood. They plan to Kevin's house, too, but he scares them off multiple times.
