En plenas fiestas navideñas, el pequeño Kevin y su familia están a punto de coger un avión para disfrutar de unas pequeñas vacaciones, pero Kevin se equivoca y embarca en un avión que lo lleva a Nueva York, donde vuelve a encontrarse solo y desprotegido.

Instead of flying to Florida with his folks, Kevin ends up alone in New York, where he gets a hotel room with his dad's credit card—despite problems from a clerk and meddling bellboy. But when Kevin runs into his old nemeses, the Wet Bandits, he's determined to foil their plans to rob a toy store on Christmas Eve.