Fifty years from now, an elevated highway spans the nation. Initially a response to international terrorism, the US government grounded commercial airline flights and built "The Black Diamond" under the guidance of project leader and chief architect, Jim Maddox. Years pass and Maddox's daughter Kate has become an engineering savant in her own right. Married to Dr. Don McLaughlin, DDS, they have an idyllic relationship; both the top of their fields and highly respected. But when the government decides to clean up the Black Diamond heading east and when Kate is kidnapped as a hostage by forces loyal to the road, Dr. McLaughlin must borrow his brother-in-law's illegal 1973 Mercury Cougar to get on the highway and rescue his wife - 150 feet above and 100 miles an hour faster than anything he's ever known! He wants his life back, he needs his wife back. It's life in the fast lane!