Star Trek Vi: Undiscovered Country (1991)

Detente comes to outer space, as the Enterprise is assigned to escort a Klingon ambassador to a peace conference with the Federation. But when the Klingon ship is inexplicably attacked, Captain Kirk and Dr. McCoy are charged with murder and hauled off to a remote alien gulag while Spock must find out who is risking the start of interplanetary war. William Shatner, Leonard Nimoy, DeForest Kelley, Kim Cattrall, and Christopher Plummer star.