Following the events of Star Trek IV: The Voyage Home, the crew of the USS Enterprise is enjoying some well deserved shore leave. The newly christened starship's shakedown cruise goes poorly and is in Earth Spacedock for repairs. In Yosemite, Captain James T. Kirk faces two challenges: climbing El Capitan, and teaching camp fire songs to Captain Spock. Unfortunately, their rest is interrupted when the crew is sent on an urgent mission to rescue hostages on the desolate planet of Nimbus III.
A Klingon commander named Klaa learns of the Enterprise's mission and pursues so that he can capture or kill Kirk. His actions are not authorized by the Klingon government, however, and he takes this quest on merely to obtain personal prestige as a warrior.