Star Trek IV starts with our heroes on planet Vulcan, loading up to go home and face punishment from the Federation for their hijacking of the Enterprise and its subsequent destruction, as well as the sabotage of the Excelsior. As they approach Earth, they find that a giant space probe is threatening to destroy the planet, emitting a signal that those on Earth are baffled how to respond to. It is determined that the probe is sending messages in the language of humpback whales, which have been extinct for over 200 years. With seemingly no obvious solution, Kirk and crew decide to time warp back to the late 20th Century to snatch a couple of humpbacks to bring back with them in the hopes of saving the Earth. They discover two whales in captivity at a San Francisco Cetacean institute. Still, they have only a limited amount of time to figure out how to transport these whales in tons of seawater, in addition to needing to harvest enough nuclear energy to send their tapped out ship back to the future. Leonard Nimoy directs.
With Star Trek II: The Wrath of Khan, the series took a swing in the exact opposite direction from Star Trek: The Motion Picture, putting things on a raw emotional level. This is a sequel, not of the first film, but of an original “Star Trek” episode, “The Space Seed”, also starring Ricardo Montalban in the Khan role. Now, it is 15 years later, and Khan and his men are marooned on a desert planet which is slated as an experiment in the Federation’s Genesis project. This project is actually a bomb of sorts that can take any uninhabited planet and make it habitable for life as we know it, transforming it into a tropical paradise. Khan hijacks a small cruiser piloted by Chekhov (Walter Koenig) and the duel between Khan and Kirk (William Shatner), the man with whom he is filled with hatred, for control of the bomb and for sheer revenge. Nicholas Meyer directs.