Doctor Who — The Invisible Enemy, Image of the Fendahl, The Sun Makers, Underworld, The Invasion of Time

Posted on October 21, 2025 by Jedadiah Leland

Having survived the Horror of Fang Rock, the Doctor and Leela resumed traveling through space and time. Along the way, they picked up a new companion named K-9. Here is the rest of the fifteenth century, which began in a British lighthouse and ended on Gallifrey.

The Invisible Enemy (1977, directed by Derrick Goodwin)

This the one where K-9 makes his first appearance.

As a story, The Invisible Enemy is no great shakes. The Doctor (Tom Baker) and Leela (Louise Jameson) materialize on a spaceship that has been infected by a sentient virus. Everyone, except for Leela, gets infected. The virus wants the Doctor to lead an infection of the entire universe. When the virus orders the Doctor to kill Leela, he breaks free from its control. He and Leela go to a space medical center, where Prof. Marinus (Frederick Jaeger) uses Leela’s natural immunity to help create a cure for the virus. At one point, the Doctor and Leela are cloned and the clones are injected into the Doctor to fight the virus. It’s a fantastic voyage for all.

Prof. Marinus’s assistant is a boxy robot dog named K-9 (voice by John Leeson). Since Marinus has to go back to Earth, he gives K-9 to The Doctor and Leela as a gift.

How you feel about K-9 says a lot about how you will feel about the remainder of Tom Baker’s time as the Doctor. Some fans consider the introduction of K-9 to be the show’s jump the shark moment. A lot more, myself included, have always liked K-9 and view him — along with the sonic screwdriver — as being an essential part of the original show’s charm. Love him or hate him, K-9, who come figure out any puzzle and who could shoot a loser from his nose, became one of the most recognizable symbols of the Tom Baker years.

Image of the Fendahl (1977, Directed by George-Spenton Foster)

The Doctor and Leela are drawn back to modern-day Earth, where scientists, witches, and cultists are all being influenced by skull that is estimated to be at least twelve million years old. The scientists assume that the skull is human but actually, it’s the skull of a Fendahl, a race of psychic vampires who developed on the legendary “Fifth Planet.” The Time Lords tried to destroy the Fendahl but one escaped in the form of a skull. It first killed all the life on Mars. (But what about the Ice Warriors and the Pyramids? Doctor Who continuity rarely added up.) Then it landed on Earth, where it influenced human evolution to create a race that it could use to its own advantage.

Image of the Fendahl feels like a spiritual descendant of The Daemons, with the same emphasis on rural British atmosphere and paganism (Leela teams up with a white witch) but without the assurance of UNIT waiting on the sidelines to take care of the threat. Image of the Fendahl, with its suggestion that humanity was specifically developed to be food, is considerably darker than The Daemons and Tom Baker, so often criticized for playing up the humor of the Doctor’s character, gives one of his more serious performances. When one of the scientists who has been possessed by Fendahl seeks to kill himself and bring an end to the threat, the Doctor hands him a gun.

Image of the Fendahl is yet another Doctor Who serial in which the main threat is revealed be the result of the Time Lords meddling. The Fourth Doctor spent a lot of time cleaning up Gallifrey’s messes.

The Sun Makers (1977, directed by Pennant Roberts)

The Doctor, Leela, and K-9 materialize on Pluto, where they discover that colonists and workers are expected to pay exorbitant taxes to the Company or risk being exiled to the Undercity. The Company’s tax collector is the Controller, who turns out to be a quivering mass of seaweed.

The Sun Makers is Doctor Who at its most satirical, poking fun at the British tax system. Apparently, the original script was much more pointed in its attacks on the Inland Revenue services but the BBC, being the BBC, demanded that the script be watered down. In human form, the Controller still clearly resembles Denis Healey, the then-Chancellor of the Exchequer.

The Sun Makers is Doctor Who at its most straight-forward, an enjoyable diversion from the more serious episodes.

Underworld (1978, directed by Norman Stewart)

The TARDIS materializes on the R1C, a spaceship that has been on a millennia-long quest to find a missing ship that was on its away to Minyos 2 and which contained the genetic files of the original Minyans who lived on Minyos 1.

This is another story where the Doctor has to deal with the bad decisions of the Time Lords. Before adapting their policy of non-intervention, the Time Lords meddles in Minyan evolution and the end result was that the Minyans viewed the Time Lords as gods and the Minyans also used all of the Time Lord technology that they had been given to fight a civil war. The Doctor feels a responsibility to help the crew of R1C complete their quest.

The R1C eventually ends up going through a space nebula and crashing into a planetoid, where they discover the ship they were searching for. The crew of the ship is being used as slaves by the Oracle, a super computer.

Underworld is one of the more boring of the Fourth Doctor’s serials. The story feels slapdash and the idea of a supercomputer was a well that the Doctor Who had already gone to far too many times.

The Invasion of Time (1978, directed by Gerald Blake)

The Doctor returns to Gallifrey and assumes his position as President of the Time Lords. He also seems to go through a total personality change, exiling Leela and announcing that a group of psychic aliens known as the Vardans will be the new masters of Gallifrey.

Leela, even after being exiled, is convinced that this is all a part of some plan on the Doctor’s part and it turns out that she’s right. The Doctor is only pretending to be allied with the Vardans so that he can discover the location of their planet and put them into a time loop. What the Doctor does not realize is that the Vardans are themselves being used by the Sontarans, who are planning on invading Gallifrey.

In retrospect, it seems inevitable that the 15th season would end on Gallifrey. It also seems inevitable that the Sontarans would eventually try to invade Gallifrey. The main threat of the Sontarans has always been that they are so stupid that they will try to invade any planet. The most surprising thing about this serial is that Leela stays behind on Gallifrey so that she can marry Andred (Chris Tanchrell), the head of the Citadel Guard. The idea of Leela living with the Time Lords has been responsible for a lot of fan fiction and it does seem unfortunate that the show didn’t do more with the idea.

Louise Jameson had already decided to leave the show and originally, Leela was to die while fighting the Sontarans. This was changed because it was felt Leela’s death would be too traumatic for younger viewers. Instead, the younger viewers were traumatized by K-9 announcing that he would be staying on Gallifrey with Leela and Andred. Luckily, for them, the final shot of the fifteen season was The Doctor looking at a crate labeled “K-9 Mark II” and smiling.

Little did the Doctor suspect that the quest for the Key of Time was waiting in his future.

Doctor Who — The Brain Of Morbius (1976, directed by Christopher Barry)

Posted on October 13, 2025 by Jedadiah Leland

The Time Lords once again decide that they need the Doctor to do their dirty work for them. The TARDIS, with the Doctor (Tom Baker) and Sarah Jane Smith (Elisabeth Sladen) on board, is sent to the rocky planet Karn.

On Karn, the crazed Dr. Solon (Phillip Madoc) lives in a castle and is kidnapping shipwrecked travelers and using their limbs to build a body for Morbius (Stuart Fell with the voice of Michael Spice). Morbius was once a Time Lord but, after being found guilty of war crimes, his body was destroyed but his disembodied brain survived. It now sits atop a makeshift body that has been constructed out of several different alien races. Solon takes one look at the Doctor’s head and decides that it would be the perfect house for the brain of Morbius.

There’s a subplot about the Sisterhood of Karn and the Elixer of Life but make no mistake. This is Doctor Who‘s take on Frankenstein, with the Baron reimagined as a mad scientist on a distant planet and the Monster reimagined as being not at all sympathetic. When I was a kid and first watching these episodes of PBS, The Brain of Morbius was one of my favorites because of the Frankenstein connection and also the look of Morbius. The original Doctor Who was known for its often-shoddy monsters but Morbius was a definite triumph. The brain sitting in a transparent bowl atop a stitched together body was one of the defining images of classic Doctor Who.

The Brain of Morbius is also known for a controversial moment during the final episode, where the Doctor and Morbius engage in a battle of the minds. On a view-screen, the faces of the three former Doctors appear, followed by several faces that had never been shown before. It was actually an in-joke on the part of production. The faces were all members of the Doctor Who crew. For decades, though, this in-joke led to a fierce debate whether or not William Hartnell was actually the first Doctor. This, of course, was back when it was still believed that a Time Lord could only regenerate 12 times. The Doctor Who revival tossed out that idea, along with a lot of other good ideas.

All these years later, The Brain of Morbius still remains one of my favorites of the Fourth Doctor’s adventures. This serial was the Tom Baker/Elisabeth Sladen era at its best.

Doctor Who — The Ark In Space, The Sontaran Experiment, Genesis of the Daleks, Revenge of the Cybermen, Terror of the Zygons

Posted on October 12, 2025 by Jedadiah Leland

The 12th season of Doctor Who got off to a shaky start with Robot, a serial that was ultimately distinguished only by the introduction of Tom Baker as the Fourth Doctor. The best thing about Robot is that it ended with The Fourth Doctor peeking out of the TARDIS and inviting Sarah Jane Smith (Elisabeth Sladen) and Harry Sullivan (Ian Marter) to join him on his further adventures. By inviting them, he was inviting the audience as well.

The remaining episodes of the 12th season not only established Tom Baker as the Doctor but it also reestablished Doctor Who as being a show about an alien who could travel through time and space. After several seasons of The Third Doctor largely staying on Earth and in the present, the 12th Season reminded everyone that the Doctor could turn up anywhere.

The Ark In Space (1975, directed by Rodney Bennett)

The first place that the Doctor takes Sarah and Harry is to Nerva, a space station that floating above the Earth. The time is 10,000 years into the future. Forced to flee the Earth due to solar flares, the crew of the space station has spent a millennia in suspended animation. During that time, the space station has been invaded by the Wirm, a space insect that has laid its eggs in some of the crewmen. When everyone is revived, the infected crewmen are transformed into creatures that are half-human and half-insect.

The Ark in Space is a classic space opera. When I was a kid and our PBS station first started to broadcast Doctor Who, they started with a four-hour bloc, which included Robot, The Ark In Space, and The Sontaran Experiment. After Robot, with its basic plot and bad special effects, it was a relief to then see The Ark In Space, a serial that lived up to all of the Doctor Who hype. Not only did Tom Baker fully step into the role of the eccentric Fourth Doctor but this serial also featured Elisabeth Sladen and Ian Marter in active roles as well. This serial said that the days of the passive companion were (temporarily) over.

The plot of The Ark in Space does have some similarities to Alien, which came out for years later. I think that’s probably just a coincidence.

The Sontaran Experiment (1975, directed by Rodney Bennett)

Having defeated the Wirm and saved the remaining colonists on the Ark, The Doctor, Harry, and Sarah transport down to Earth to repair a receiver terminal. They discover that the Earth is not as deserted as they assumed. A group of human astronauts returned to the planet earlier but they were captured by Styre (Kevin Lindsay), a Sontaran who has been sent to Earth to prepare it for an invasion so that the Sontarans can use the planet as an outpost in their never ending war with the Rutans.

This serial was only two episodes long but The Sontarans were always good villains. They’re relentless, destructive, and very, very stupid. This story featured one of Tom Baker’s best moments, when he convinced Styre to throw away his weapon because it made him look weak. Styre fell for it because Sontarans will fall for anything.

Genesis of the Daleks (1975, directed by David Maloney)

This is it. This is the first true classic of the Tom Baker era and also the best of the classic Dalek stories. Terry Nation was invited back to Doctor Who to write about his most famous creations and he created one of the show’s most enduring villains in the process.

A Time Lord appears to the Doctor and his companions and tells them that they need The Doctor to change history. (This goes against all Time Lord law, which is why they gave the job to a known renegade like The Doctor.) The Daleks have been determined to be too much of a threat. The Doctor is to go back to the time of their creation and “interfere.”

The Doctor, Harry, and Sarah Jane find themselves on Skaro, where the war between the Thals and the Kaleds have left the planet ravaged and inhospitable. The Thals and the Kaleds each live in a domed city and spend their days shooting missiles at each other. Terry Nation often said that the Daleks were meant to be a stand-in for the Nazis and he makes that clear in this episode with the Kaleds wearing SS-style uniforms and spouting theories about racial superiority.

In this episode, Nation introduces Davros (Michael Wisher), the horribly scarred and crippled scientist who will ultimately be responsible for transforming the Kaleds into the Daleks. (The Kaleds who don’t want to be Daleks are wiped out by those who do.) Davros would appear in every subsequent Dalek episode of classic era Doctor Who and his effectiveness would be diluted by repetition. In his first appearance, though, he immediately establishes himself as a frightening and truly evil Doctor Who villain. If their first appearance suggested that the Daleks retreated into the shells for survival in their nuclear-ravaged world, this episode shows that it more about Davros wanting to play God.

A six-episode serial, Genesis of the Daleks more than justifies its epic length. The heart of the serial is a moment when the Doctor, on the verge of wiping out the Daleks forever, stops to wonder if he has the right to do so. This was a key moment in the development of The Fourth Doctor. The Fourth Doctor may have been an eccentric but he was an eccentric with a conscience who realized that even the worst creatures deserved a chance at redemption. In the end, The Doctor does not destroy the Daleks, though he does set back their evolution by an undetermined number of years. As the Doctor explains it, good will always rise up to counter the evil of the Daleks.

This episode features the apparent destruction of Davros but you can never keep a good villain down. Both Davros and his creations would return.

Revenge of the Cybermen (1975, directed by Michael Briant)

After a classic Dalek story, I guess it was inevitable that Doctor Who would feature a Cyberman episode.

Following the events of Genesis of the Daleks, the Time Lords return The Doctor, Sarah Jane, and Harry to the Nerva space station. They arrive several centuries before the events in The Ark In Space. Without the TARDIS (it’s traveling back through time to meet them), The Doctor and his companions discover that the majority of Nerva’s crew is dead and that the remaining members are using the station as a space beacon to warn people about a drifting planetoid. The planetoid is made of gold and the Cybermen show up at Nerva because, being uniquely vulnerable to gold dust, they want to destroy it.

If Genesis of the Daleks re-imagined the Daleks, Attack of the Cybermen proves to be just a typical Cybermen story and a disappointing one. The best thing about this episode is that it gave Tom Baker a chance to once again prove his Doctor bonafides by defeating a classic Doctor Who villain.

Terror of the Zygons (1975, directed by Douglas Camfield)

Terror of the Zygons was the first seral of the thirteenth season but, since it’s also Harry Sullivan’s final appearance as a regular member of the TARDIS crew (though he would return in a later episode for a one-off appearance), it still feels like a twelfth season episode.

Having been reunited with the TARDIS, the Doctor, Sarah Jane, and Harry return to present-day Earth. The Brigadier (Nicholas Courtney) and UNIT are investigating attacks on oil rigs by a giant sea creature. Sea Devils, again? No, this time it’s the Zygons, who are far less sympathetic.

This was a typical UNIT story, the type of thing that Jon Pertwee did regularly. Tom Baker’s more mischievous version of the Doctor feels slightly out-of-place with UNIT but it is still a pleasure to see Nicholas Courtney and John Levene again and this episode finally explains what everyone has been seeing in Loch Ness over the years. This episode ends with Harry returning to UNIT while Sarah Jane and the Doctor returned the TARDIS. Harry Sullivan was a strong character and producer Philip Hinchcliffe later said it was a mistake to write him out of the series.

Ian Marter, who played Harry Sullivan, continued to be associated with Doctor Who as one of the better writers of the Doctor Who novelizations. He also wrote two stand-alone novels featuring Harry’s adventures without the Doctor. Ian Marter died of a heart attack when he was just 42 but Harry Sullivan lived on, frequently being mentioned in both the classic series and the revival.

That’s it for the 12th season, the season that truly made Tom Baker the Doctor and which was one of the best of the classic series. As these were the first episodes of Doctor Who that I ever saw, I have a lot of nostalgia for them. The Ark In Space, The Sonatarn Experiment, Genesis of the Daleks, and even Terror of the Zygons still hold up well to this day.