Synopsis: Terrorists have planted a deadly virus on a transcontinental train. On board are the glamorous Jennifer Chamberlain and her ex-husband, Dr. Jonathan Chamberlain, as well as Nicole Dressler and her young lover, Robby. They can't get off, and one solution proposed is to quarantine them by rerouting the train over the Cassandra Crossing -- an unstable bridge. Dr. Chamberlain wants to save them, but has to battle the terrorists first.