Star Trek: Season 2, Episode Twenty “Return to Tomorrow”

Stardate: 4768.3 (2268)
Original Air Date: February 9, 1968
Writer: John T. Dugan (credited as “John Kingsbridge”)
Director: Ralph Senensky

“Risk is our business. That is what this starship is all about.”

Rating: 5 out of 5.

Mr. Sulu returns! The Enterprise is traveling through deep space, hundreds of lightyears past where any Earthship has explored before. They are tracking a signal from a seemingly lifeless planet –a Class M planet– a place which has been dead for a half million years after its atmosphere was mysteriously ripped away. As the Enterprise approaches, a disembodied voice named Sargon (voiced by James Doohan) suddenly booms throughout the ship: “all your questions will be answered.” Since exploration and contact with alien civilizations is the Enterprise’s primary mission, Kirk decides to risk engaging with the voice. As the ship’s sensors reach outward, planetary coordinates are transferred and Sulu is left at the helm.

Kirk, Spock, Dr. McCoy, and an astrobiologist named Dr. Ann Mulhall (Diana Muldaur) are all beamed down to the planet even though Scotty has not yet manned the controls –two redshirt security officers are left behind. The crewmen are beamed into a subterranean chamber composed of an unknown substance located beneath 112,37 miles (not kilometers) of rock. The chamber was apparently constructed about a half million years ago, around the same time that the planet’s atmosphere was destroyed.

A door opens to reveal a beaming orb who soon identifies himself as the godlike being, Sargon. Spock uses his tricorder to reveal that the voice behind the orb is wholly composed of energy without substance, or matter without form. Sealed inside is the essence of Sargon’s mind. Sargon tells his story to the Enterprise crewmen (whom he refers to as “my children”). He belongs to an ancient race of beings who once left their seed on various planets, including on Earth. Are we to believe these beings are the founders of humanity? Sargon suggests creation myths on Earth (i.e. Adam and Eve) were likely inspired by two of his fellow beings. As time passed, Sargon and his people became so powerful that they believed themselves to be gods They developed new technologies, and faced a massive nuclear holocaust which nearly annihilated their whole race. In time, their records were lost. Only the best minds were selected to be preserved in this chamber, and for centuries Sargon has been probing the heavens with his mind, hoping to entice a starship to visit this distant corner of space. Sargon and his people lost the ability to remain in their corporeal bodies centuries earlier, and now Sargon has beckoned the Enterprise to his planet in order to request temporary use of the crewmen’s bodies. Why? He wants to construct a trio of android humanoid robots so that he and his two surviving compatriots can experience a modicum of mobile life again. Despite being all-powerful, Sargon is somehow unable to build the androids himself, and he is surprisingly respectful when requesting the right to inhabit a human body. Naturally, inhabiting another body comes with consequences. When Sargon enters Kirk’s body, Kirk’s heart action doubles (262 beats per minute), his body-temperature rises to 104 degrees, and his metabolic rate is pushed into overdrive causing rapid deterioration. Kirk will soon die if Sargon does not vacate his body.

Once he leaves, Kirk and the crew deliberate over whether or not to allow these beings to inhabit their bodies so they can build the robots they need. Most seem skeptical until Spock notes that these beings could help humanity leap forward 10,000 years. Dr. Mulhall is interested for scientific purposes, and Kirk passionately defends the risky objective of the Enterprise’s ten-year mission in the first place. Thus, against Dr. McCoy’s initial hesitations, the crew decides to take the risk of supporting these alien beings.

We then meet Sargon’s two other surviving beings: his wife Thalassa, who inhabits Dr. Mulhall’s body, and Henoch, a smilingly mischievous character who enters the body of Spock. These two then begin to develop a “metabolic reduction injection” which allows them to remain inside the crewmen’s bodies for longer periods of time, while also building their robots. It gets a bit complex and muddled in the fourth act, but despite plans to help humans not to make the same mistakes, the power-hungry Henoch devises a plot to remain inside Spock’s body. He tries to sabotage Sargon by disrupting Kirk’s injections, destroying the orb receptacles, and eliminating Spock’s consciousness, however the plan ultimately backfires. Amidst a false poisoning scheme, Henoch is forced to flee Spock’s body into oblivion (in truth, Sargon actually did survive as did Spock while secretly hidden inside Nurse Chapel’s body). Sargon and Thalassa then embrace for one final moment before they too dissipate into oblivion –they share a kiss in Kirk’s and Dr. Mulhall’s bodies before passing away. After they pass, the attractive Dr. Mulhall gazes longingly at Kirk and says she was “only too happy to cooperate, captain.”


The chief theme in this episode is risk. How is it managed? How is it tolerated? At what point does the risky mission of the Enterprise border on self-harm? In this case, Sargon proves to be a rare trustworthy godlike being who manages to quickly earn the trust of the crew, though most other gods in the Star Trek universe are met with justified skepticism. Sargon offers an optimistic vision of helping humanity to advance well beyond its years (I guess Sargon has no Prime Directive of his own to follow). However, looking at Sargon is almost like witnessing a chilling vision of the future of humanity, one that is driven underground by nuclear war, unable to live and breathe in a body any longer, simply existing as a ball of consciousness trapped inside an orb receptacle. Are humans doomed to meet the same fate as Sargon? The future looks grim from this vantage point, though Kirk acknowledges that humanity had managed to overcome its own nuclear age.

I thought there were some great ideas explored in this adventure –I was reminded of the Enterprise’s recent run-in with Season 2’s “The Gamesters of Triskelion” where Kirk was also brought underground, deep below a planet’s surface into a bunker housing a trio of brains protected behind glass spheres. In “Return To Tomorrow” there is also a splendid new score written by George Duning, and Leonard Nimoy’s acting shines as he plays the duplicitous Henoch (I don’t think we have seen Spock smile since “The Cage”), but the zenith of this episode comes from Kirk’s impassioned “risk is our business” speech, which is one of the best examples of William Shatner’s “Shacting” yet!

However, I was also puzzled by a number of things here: How can a planet that registers as “Class M” also have its atmosphere ripped away? Would it still be breathable? And if Vulcans have superior bodies to inhabit, why would Sargon not simply lure a Vulcan ship instead of the Enterprise to his planet? Wouldn’t that avoid the same issues with metabolic reduction? And how is it possible that Sargon et al are extremely powerful yet they have only managed to encase themselves in tiny spherical orbs? If they can commandeer the Enterprise’s transporter, why can they not build the androids they need? Also could it have been possible to glean some valuable insights or knowledge from Sargon and Thalassa before they depart into oblivion? Did they need to leave so soon? Were there any other places for their consciousness to reside so they could still help humanity? Lastly, we have seen numerous instances of security breaches aboard the Enterprise, but perhaps this one takes the cake. The crewmen give over their corporeal bodies with almost no guarantees of return from Sargon. In this case, the Enterprise simply got lucky in finding a benevolent godlike alien.


Writer John T. Dugan (1920-1994) was inspired to write this script based on an article about highly sophisticated robots. He later received a Writer’s Guild nomination for this episode. As a Catholic, Dugan intended for Sargon and Thalassa to continue floating around the cosmos as incorporeal spirits, however Gene Roddenberry gave the script some uncredited rewrites which made it so that they faded into oblivion. In anger, Dugan asked that his name be changed in the credits to “John Kingsbridge.” Personally, I think Dugan’s initial idea would have been silly, and Roddenberry’s notion of “oblivion” adds to the force of the episode’s conclusion. It requires considerably greater courage to willingly face the prospect of oblivion, rather than an unending “afterlife.”

Director Ralph Senensky (1923-Present) dubbed this episode the one with the “huge ping pong balls.” He has also declined to speak about it too much, perhaps hinting that it was a bit of production mess behind the scenes. Joseph Pevney was originally slated to direct this episode but he quit the series after “The Immunity Syndrome” citing a lack of discipline after Gene L. Coon departed the show.

Star Trek Trivia:

  • George Takei returned to his role as Sulu in this episode after a hiatus lasting since “I, Mudd.” He was away while filming The Green Berets (1968), a John Wayne film.
  • The three alien names in this episode allude to a rich panoply of mythology. According to Greek mythology, Thalassa was the goddess of the sea; Sargon the Great was one of the earliest emperors in human history as ruler of the Akkadian Empire during the 24th and 23rd centuries BC; and Henoch is likely an allusion to Enoch in the Bible –a grandson of Adam who did not die of natural causes but was rather “taken by God.”
  • This episode was the first appearance of Diana Muldaur in the Star Trek franchise. She returned again as Dr. Miranda Jones in the third season episode “Is There in Truth No Beauty?” and then again as Dr. Katherine Pulaski in the second season of TNG.
  • Fans have noted that Dr. Mulhall should be wearing a blue shirt rather than a red shirt according to her rank in Starfleet.
  • Dr. McCoy’s hesitance to engage with Sargon is similar to his reservations in Star Trek II: The Wrath of Khan regarding beaming down to Regala I.
  • According to later Treklore, the name of the planet in this episode (which is unmentioned onscreen) is Arret, perhaps an inversion of the Latin word “Terra.”)
  • William “Billy” Blackburn was a regular background performer in TOS, often playing a helmsman or navigator believed to be named “Hadley.” He appears briefly in this episode as the humanoid robot in latex make-up with only the whites of his eyes visible. In recent years, some of his personal silent homemade footage from behind the scenes of Star Trek has surfaced.

Click here to return to my survey of the Star Trek series.

1 thought on “Star Trek: Season 2, Episode Twenty “Return to Tomorrow”

  1. You make some very interesting points about this episode. Incredibly advanced ET beings in Star Trek can quite often be creatively problematic. Even if they still do wonderful things like averting devastating wars as the Organians did in Errand Of Mercy. It’s therefore all the universally endangering stories when such beings should intervene yet somehow don’t, like The Alternative Factor, The Doomsday Machine and The Immunity Syndrome, that are consequently all the more questionable. I now just remember Return To Tomorrow for the lovely Diana Muldaur’s first contribution to the Trek universe. Thank you for your review.

    Liked by 2 people

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