Ten years after a covert military experiment on a remote Pacific island went wrong and killed eighteen servicemen and his assistant, Dr. Richard Long is still trying to forget the havoc that the experiment caused. Living in the small town of Jerome, Montana, Long still does scientific experiments at the local base, and he enjoys his time fly-fishing with Tim Mason, who works at a local diner. Long is visited by Colonel Andrew Brynner, a former military officer who took the blame and served ten years in Leavenworth Federal Prison for Long's experiment. Now a free man with a score to settle, Brynner has assembled a team of terrorists, including an icy blond named Vaughn. Brynner plans to steal and then sell "Elvis" -- Long's highly volatile, blue crystal substance -- to the highest international bidder. Unfortunately for him, Long, who gets killed, has already delivered "Elvis" to Mason, along with directions that the substance must remain below fifty degrees Fahrenheit, or it will detonate and vaporize everyone within several hundred miles of it. After Mason and Arlo, a wisecracking ice cream delivery man, have a run-in with Brynner, they try to get the substance to Fort Magruder. They don't exactly get along with each other -- Arlo only agrees to transport the substance in his ice cream truck because Mason held a gun on him -- but they find a common bond in trying to avoid Brynner, who will stop at nothing to get the substance.