Rick Brant and his good friend Dan Scott are attending a scientific conference in Denmark with Rick's father, Dr. Hartson Brant, when an urgent midnight phone call to their Copenhagen hotel room involves them in one of the strangest adventures either has ever encountered. A top U.S. security agency fears that Dr. Harold Keller, one of the American scientists attending the conference, may be in danger. The boys are ordered to keep him under close observation.

     Thus begins a thrilling chase by sports car, taxi, train, and jet that spans three countries and ends in a hideout high in the Swiss Alps. But Rick and Scotty are not alone as they pursue the elusive Dr. Keller. Involved also are the mysterious "Blue Beret," "Pretzels," and "Felt Hat," members of rival organizations. Who are these men? Why do they want Dr. Keller and the ruby laser he has developed for use in delicate surgery? In search of answers to these and other questions, Rick and Scotty find their endurance, bravery, and ingenuity tested to the absolute limit in an unusual and electrifying suspense story that will have the reader guessing to the very end.