John Dennehy is at odds with his Irish father Michael, who's come from the old country to visit his son's family in America. From the time he arrives, the elderly Dennehy has been talking with the wee folk, tiny magical beings who hitched a ride in his suitcase, and are invisible to all non-believers. Soon the crafty leprechauns discover a foul pot-a-brewin,  John has secret plans to build a theme park over their enchanted lands in Ireland.