TOS: S1 – E5: The Enemy Within

The Enemy Within
The Enemy Within | Courtesy of CBS / Paramount

STARDATE: 1672.1

The episode begins with the Enterprise in orbit over planet Alpha 177. The crew is below on a specimen-gathering mission. Sulu was carrying around an alien creature.… a pink “dog” with a horn coming out of the center of its face. There is soon an accident.

Geological Technician Fisher slides down the side of a rocky cliff. He is not badly hurt, but Kirk orders him to beam back aboard the Enterprise and report to sickbay, as he is covered in the dusty of some metallic ore.

During the transporting process, there is some difficulty. Scotty checks things over and then beams the captain aboard. As he materializes, Kirk stumbles and holds his forehead. Scotty helps Kirk out of the transporter room, and as they exit, another James T. Kirk is beamed aboard.  This one has a sinister look in his eye.

The duplicate Kirk ignored Crewman Wilson when he asked if the captain needed assistance.

Meanwhile, the real captain wandered back to his cabin and spoke to Yeoman Rand, who gave him the ship’s manifest. He then went to sleep.

As Dr. McCoy worked on healing Fisher, the duplicate Kirk entered sickbay and said “Saurian Brandy.” McCoy shooed Fisher away and asked Kirk what he needed, and Kirk grabbed him around the neck and yelled: “I said Saurian Brandy!” The doctor opened a cabinet and gave him the drink. Kirk took the brandy and left sickbay. He wandered the corridors of the ship drinking until he found Yeoman Rand’s quarters. He entered and waited.

The Good Dog
Kirk, Spock and Scotty examine the “good” creature before looking at its opposite. Courtesy of CBS / Paramount

At the same time, Mr. Spock asked the real captain if there was anything he could do for him. Spock said he was there because Dr. McCoy told him that Kirk needed to be checked on. Spock relayed to Kirk the behavior of his double. Kirk laughed.

Later Scotty found that there was indeed a transporter issue. Apparently, the creature that Sulu had been carrying, the docile pink “dog” also had a double, and it was very aggressive. Scotty said it was more than a duplicate — it was an opposite.

At that moment, Yeoman Rand returns to her quarters, with an evil Kirk lurking. Rand asked if he needed anything. He said that she ought to call him Jim and that she was too beautiful to ignore. He then grabbed her and to her to “stop pretending!” He then told her not to fight him… and he kissed her. There was then a struggle, and she scratched his face. Rand was able to get to her door and call to Fisher. “Call Mr. Spock!” she screamed.

The evil Kirk then raced out of Rand’s cabin and attacked Fisher before he could message Spock.

Spock did respond to the alert and confronted the captain in his quarters. It must be noted that the good Kirk is wearing the green-yellow tunic wrap, while the evil Kirk is wearing the standard gold Starfleet command uniform. Kirk denied this accusation, so he and Spock went to sickbay to straighten it out.

The evil Kirk was scurrying around in the shadows and entered the captain’s quarters, wounded and bloody.

Rand recounted her story in front of the good Kirk. She told Kirk how he started to hurt her, and how she had to scratch his face to get him off of her. Kirk then said her to look at him — noting that there were no scratches. She told him that Fisher saw him too. Fisher got out of the bed and told Kirk to his face that the captain was the one doing the attacking.

Spock declared there was only one logical answer — there was an impostor aboard.

Things started to become tense aboard the Enterprise, as Kirk began to worry about the falling temperatures on the surface — which would go to below -120 F at nightfall. Mr. Scott cautioned against using the transporter until the mystery as to why the duplication was solved.

Scotty apologized, saying that the engineering team was doing “everything we can.”

Spock posed that killing the captain’s double could harm Kirk himself. Kirk agreed but ordered that the search parties scour the ship for his double, with phasers locked on setting number one. Kirk also told Spock to tell the crew the truth, but Spock pushed back, telling him that he did not have the right to be vulnerable in the eyes of the crew. If he did, then the crew might lose faith in him as a leader. Kirk agreed.

Later, Kirk noticed that his will to make decisions was becoming more difficult. But even as he thought that he warned the crew that his double was on the loose and that all can recognize him by the scratches on his face. As the announcement rang out all over the ship, the evil Kirk trashed his quarters, yelling “I’m Captain Kirk!” He attempted to cover up the scratches with some sort of makeup.

He walked out of the cabin and encountered Crewman Wilson. He ordered Wilson to give him his phaser, and then Kirk attacked Wilson.

On the surface, Sulu and the other crewmembers were starting to freeze on the surface of the planet. Spock then learned that Wilson had been disarmed and then attacked.

Spock attempted to out-guess the double and try to predict where he will appear next. Kirk says that he would try to hide on the lower levels of the ship. They go together to try to capture the double.

As they patrol the lower levels, the double stalks them. The two kirks finally come face to face. The original Kirk tries to reason with his double, and as he does, Mr. Spock gives him the Vulcan neck pinch, rendering him unconscious. But just before that happens, the evil Kirk discharges his phaser into a column, leaving a smoking hole.

Kirk complains that he is changing. Spock says that the evil side is part of him and that his power of command will start to slip away. Oh and that column that the evil Kirk shot earlier? It turned out to be a component of the transporter, which now will not work at all. Scotty says that it will take at least one week to repair.

Sulu contacts the ship again, as the temperature continues to fall. He resorts to using a phaser to heat rocks to stay warm. Due to the captain’s ineffectiveness, Spock has had to take over many duties.

The evil Kirk remained in sickbay under McCoy’s watch as he begins to die… for reasons unknown. Kirk comforts his double and calms down his evil version. It is then that he declares that he must reincorporate this evil version into himself. McCoy agrees, saying that the fire of the evil Kirk is where his strength of command comes into play, while the calm Kirk retained the logic and goodness.

Scotty and Spock tinkered with the transporter and were able to get it working temporarily. They attempt to transport the bad dog and good dog back to the planet’s surface and back, hoping that they merge back together. The experiment did not work.

“He’s dead, Jim,” reported McCoy.

McCoy speculates that the animal died aftershock. Spock agreed, but he speculates that the fact that Kirk has his wits and the dogs did not. But after some back and forth between McCoy and Spock, it was clear that whoever had the last word, the captain would agree with that point of view. Kirk asks them to decide for him. But they refuse. He then orders Spock to ready the transporter, and he urges McCoy to do an autopsy on the animal.

double kirk
Too much Shatner? Perhaps. But our planet might not be able to handle two William Shatners. Courtesy of CBS / Paramount

On the surface, Sulu calls again as it now -117 degrees. As Kirk listens to Sulu, the evil Kirk listens as well. He then decides to do something to save Sulu and the others. Kirk unstraps his double and tells him that they must go through the transporter together. The evil Kirk says that he won’t fight anymore and that he feels weak and immediately attacks. The evil Kirk then gets an identical greenish tunic wrap and puts it on.

Evil Kirk sees Rand in the corridors and stops to give her an explanation. He tells her that he’d like to come to her cabin later to discuss what happened. She agrees reluctantly. Kirk then heads to the bridge, where he immediately orders the Enterprise to leave orbit. Mr. Farrell argues, but Kirk says they cannot be saved. Spock notes that this was not the plan, but Kirk tells him to return to his station.

As evil Kirk sits in command, good Kirk comes up from the turbolift with McCoy. Evil Kirk tries to get Spock to arrest the good Kirk. Harrell asks Spock who to believe, but Spock stands next to good Kirk. As he knows there is no way out, evil Kirk begins to yell and scream and attacks crewmen. Evil Kirk threatens to kill good Kirk, but then the two Kirks embrace.

Together they step into the transporter. Kirk orders Spock to kill him if the merger does not work. Spock beams down two Kirks, and only one returns. Spock and McCoy are not sure which Kirk came back, but they know for sure when the captain orders Spock to beam Sulu and the others back “fast.”

Kirk returned to the bridge and told Spock to forget about the “impostor.” Rand then tells Kirk that the impostor told her what had happened. She said that she wanted to tell him something … but Kirk cut her off before she could. Spock then told Rand that the impostor had some “interesting qualities.”


In what has now become a movie and TV cliché, Kirk faced himself. Sort of like when Elvis met himself in 1964’s Kissing Cousins, there were lots of exciting moments and camera angles that had to be created for this episode. But one screaming detail that the writers chose to ignore … was the SHUTTLECRAFT. Why didn’t they just send a shuttle down to pick up Sulu? They could have made up a reason why the shuttlecraft was out of commission. Instead, they just left a big ol’ plot hole. Even still, this was a fun episode. A few classic lines were uttered here for the first time, and there was an excellent Spock vs. McCoy debate.

RATING: 3.5 out of 5

Directed by: Leo Penn
Written by: Richard Matheson
Produced by: Gene Roddenberry
Associate Producers: Robert H. Justman, John D. F. Black
Director of Photography: Jerry Finnerman
Art Directors: Roland M. Brooks, Walter M. Jefferies
Theme music by: Alexander Courage
Music composed and conducted by: Sol Kaplan


William Shatner as Kirk
Leonard Nimoy as Spock


DeForest Kelley  as Dr. McCoy
Grace Lee Whitney as Yeoman Rand


George Takei as Sulu
James Doohan as Scott
Edward Madden as Fisher
Garland Thompson as Wilson
Jim Goodwin as Farrell

Film Editor … Fabien Tordjmann
Assistant to the director … Edward K. Milkis
Assistant Director … Greg Peters
Set Decorator … Carl F. Biddiscombe
Costumes created by … William Theiss
Post Production Executive … Bill Heath
Music Editor … Robert H. Raff
Sound Editor … Joseph G. Sorokin
Sound Mixer … Jack F. Lilly
Photographic Effects … Howard Anderson Co.
Script Supervisor … George A. Rutter
Music Consultant … Wilbur Hatch
Music Coordinator … Julian Davidson
Special Effects … Jim Rugg
Property Master … Irving A. Fenberg
Gaffer … George H. Merhoff
Head Grip … George Rader
Production Supervisor … Bernard A. Windin
Makeup Artist … Fred B. Phillips, S.M.A.
Hair Styles by … Virginia Darcy, C.H.S.
Wardrobe Mistress … Margaret Makau
Casting … Joseph D’Agosta
Sound … Glen Glenn Sound Co.

Executive in Charge of Production … Herbert F. Solow