When an entire solar system begins to disintegrate into cosmic rubble, Captain Kirk suspects that rumors of a new Klingon super weapon are all too true. The Tautee system houses a flourishing pre-warp civilization not quite ready to join the Federation, so the Prime Directive limits Kirk's ability to undo the disaster, and his humanitarian rescue operations provoke a hostile response from four Klingon warships.

What is destroying the Tautee system? The U.S.S. Enterprise must uncover the truth before the catastrophe extends beyond Tautee to threaten the very nature of reality itself.