Star Trek VI: The Undiscovered Country

In 2293, the starship USS Excelsior, commanded by Captain Hikaru Sulu, is struck by a shock wave, and discovers that Praxis, a Klingon moon, has been destroyed. The loss of Praxis and the destruction of the Klingon homeworld's ozone layer throws the Klingon Empire into turmoil. No longer able to maintain a hostile footing, the Klingons sue for peace with their longstanding enemy, the United Federation of Planets. Accepting the proposal before the Klingons choose to revert to a more belligerent approach and die fighting, Starfleet sends the USS Enterprise-A to meet with the Klingon Chancellor, Gorkon, and escort him to negotiations on Earth. Captain James T. Kirk, whose son David was murdered by Klingons, opposes the negotiations and resents the assignment.