Threatened by a deadly famine, the Klingon Empire is on the verge of igniting a mad interplanetary war of conquest.
When an earthquake destroys a remote Federation research station, Jean Czerny, agricultural scientist, succumbs to amnesia. Stranded on enemy borders, she is imprisoned by Kang, the commander of a Klingon battleship.
Now Kirk must play a dangerous game of mind strategy to prevent a savage attack on the Federation!