Jerry Harper is back home, recovering from his injuries. It won't be for long. He's a strategic asset now, and the government is eager to send him back into action. They want to protect him better on his next war patrol, so he's assigned to a new station: the Agrarian Commonwealth's new battleship. He and the fleet soon jump out and begin their mission.
While in space, horrifying news arrives. The Reliants have invented a doomsday weapon, a virus that targets the Agrarian genetic code. They begin deploying it, and Agrarians are killed by the billions. Jerry is tasked with using his electrokinesis to find the virus's production facility so that a coordinated attack can be made. It might be the only chance the Commonwealth gets before the galaxy's Agrarians are exterminated.
Jerry's health is in rapid decline due to his electrokinesis. He can't afford to push himself. But a Rifleman does his duty, even if it kills him.