The supercomputer Sybil has a new mission for the U.S.S. Endeavour: Fly into the middle of an interplanetary war and kidnap an instrumental physicist from a pre-warp civilization—without violating the Prime Directive.

Sybil warns the crew that the scientist is frighteningly close to pioneering a method of destroying entire planets using a matter-antimatter reaction from vast distances. Commander Tendi is skeptical that someone without warp technology could invent such a weapon, but Captain Raffi is convinced by Sybil’s conviction and insists the crew of the Endeavor must persuade Maryuliz IV and V to end their conflict before his idea of a weapon can be conceived.

The fate of the Federation may rest with one man’s decision to pursue peace…or destruction.