Earth barely survived the 21st Century. Biotechnological and nuclear terrorism, civil war, famine, and ethnic cleansing killed billions. Thousands fled on warpdrive ships to colonize planets around distant suns.
In the 22nd century, after the United Nations established control over Earth, it opened wormhole links to the distant colonies, to prevent a repeat of the previous century's chaos on a galactic scale.
Enter operative Stone Chalmers. Spy. Assassin. Instrument maintaining the UN's order on the settled galaxy.
Opposing him are hostile forces on colony worlds... and within the UN itself.