The Enterprise and crew return to Spacedock for repairs. When they arrive, they are shocked to discover that the Enterprise is to be scrapped. Spock is dead and McCoy is, seemingly inexplicably, going insane. An unexpected visit from Sarek, Spock's father, provides a startling revelation: McCoy is harboring Spock's katra — his living essence. With the help of his friends, Kirk steals the Enterprise for one last mission — to retrieve Spock's body from the Genesis planet.

William Shatner (Admiral James T. Kirk)
Leonard Nimoy (Captain Spock)
DeForest Kelley (Dr. Leonard H. McCoy)
James Doohan (Capt. Montgomery Scott)
Walter Koenig (Cmdr. Pavel Chekov)
Nichelle Nichols (Cmdr. Uhura)
George Takei (Cmdr. Hikaru Sulu)

Mark Lenard (Ambassador Sarek)
Merritt Butrick (Dr. David Marcus)
Dame Judith Anderson (Vulcan High Priestess T'Lar)
Robin Curtis (Lt. Saavik)
Christopher Lloyd (Commander Kruge)
Phillip Richard Allen (Captain J. T. Esteban)
James B. Sikking (Captain Styles)
Phil Morris (Trainee Foster)
Scott McGuiness (SF Transporter Tech "Mr. Adventure")
Robert Hooks (Harry Morrow)
Cathie Shirriff (Valkris)
Stephen Liska (Torg)
John Larroquette (Maltz)
Jeanne Mori (Grissom Helm Officer)
Mario Marcelino (Grissom Comm Officer)
Miguel Ferrer (Excelsior First Officer)

• This movie picks up where Star Trek: The Wrath of Khan left off.
  
• Though Spock died at the end of the previous movie, the studio was able to entice Leonard Nimoy to return by allowing him to direct this movie. His name does not appear in the opening credits with the rest of the cast.
  
• This movie marks the debut of the Excelsior-class starship, namely the U.S.S. Excelsior NX-2000. At this time, the newly commissioned Excelsior was a test-bed for the transwarp drive.
  
• This movie also debuts the Oberth-class starship, the U.S.S. Grissom NCC-638. The Grissom, commanded by Captain J.T. Esteban, was assigned to study the Genesis Planet. Lt. Saavik was assigned as the Grissom science officer. The Grissom was destroyed by the renegade group of Klingons, led by Kruge.
  
• Scott is promoted to Captain.