Nick Jenkins works with a group of engineers on asteroid Freedonia, attempting to build the first CT reactor. A contraterrene matter (CT, or antimatter) reactor will provide enough power for the entire solar system, freeing people from the tyranny of limited fission power monopoly controlled by the Interplanet corporation. A surprise attack on Freedonia by unknown attackers results disables the entire staff save for Nick Jenkins. The entire staff, including Jenkins, is exposed to a lethal dose of radiation. They will all die within two weeks.
Now it up to Nick Jenkins to track down the attackers, prevent the outbreak of a CT war, and finish the CT reactor in order to provide free power to the solar system. And he must do so before he dies of radiation sickness.