The Gunsmith is asked to protect a scientist who is delivering a buckboard load of materials to his laboratory on an island off the coast of Galveston, Texas. More for something to do rather than the money he is promised, Clint agrees. Very quickly it becomes evident that some men are after the scientist, and his product. Clint discovers the scientist is working on something that is potentially very dangerous. The scientist's heart is in the right place. He informs Clint that his invention will be a boon to mankind. But he doesn't realize how badly his invention can be misused. It's a typical situation of something being created for good, but being used for evil. Finally, Clint has to work with the scientist and his lovely assistant to keep the men who are coming after him from killing the three of them, stealing his invention, and weaponizing it.