Spoilers are precisely defined here. Rules vary by the story's medium. Info from television stories can't be added here until after the top or bottom of the hour, British time, closest to the end credits roll on BBC One. Therefore, fans in the Americas who are sensitive to spoilers should avoid Tardis on Sundays until they've seen the episode.



Galaxy 4 was the first serial of season 3 of Doctor Who.

It was recorded after The Time Meddler as part of the series' second recording block. Its third episode, "Air Lock", achieved the highest ratings of any episode between the final episode of The Web Planet and the final episode of The Three Doctors. Indeed, "Air Lock" is one of the few episodes from pre-BBC Wales Doctor Who to have ranked amongst the top fifteen shows of its initial broadcasting week.[1]

Galaxy 4 is the earliest non-historical story to have missing episodes. Until the recovery of "Air Lock" in 2011,[2] it was notable for the extreme paucity of its surviving material. Because no telesnaps were taken during broadcast, photographic evidence for this story was effectively limited to publicity shots (with only one photograph of the Rills) and a six-minute excerpt from "Four Hundred Dawns". "Air Lock" currently remains the only existing episode of the serial.

Actor Peter Purves has been outspoken in his distaste for the serial, which was originally written for Ian, Barbara and Vicki. He has frequently opined that his character, companion Steven Taylor, was not well-served because the hurried rewrite mostly transferred Barbara's lines to him, resulting in a "feminisation" of Steven's character.

The story was released on DVD, Blu-Ray and Limited Edition Steelbook on 15 November 2021, with all four episodes animated in both black-and-white and colour, including the surviving episode three.[3] Furthermore, there was a special screening of the four animated episodes at the BFI Southbank on 7 November, followed by a Q&A attended by Peter Purves.[4]


The Doctor, Vicki and Steven arrive on an arid planet where they meet the beautiful Drahvins and the hideous Rills. Each has crash-landed after a confrontation in space. The Rills are friendly, compassionate explorers. The Drahvins are dull-witted, cloned soldiers, terrorised by the intelligent, warlike matriarch Maaga.

Both ships are damaged. The Drahvins' craft is irreparable, whereas the Rills' is almost ready to take off; however, the Rills have been unable to find a compatible fuel source. Although unable to breathe the oxygen atmosphere, they employ efficient robot drones, which Vicki nicknames "Chumblies". Despite numerous offers by the Rills to take Maaga and her crew to safety, she refuses their aid. When the planet is discovered to be on the point of disintegration, Maaga tries to force the time travellers to help her steal the Rills' ship and kill the Rills. Instead, the Doctor allows the Rills to draw power from the TARDIS to refuel and escape, leaving the Drahvins to their fate.


Four Hundred Dawns (1)[]

The First Doctor, Vicki Pallister and Steven Taylor arrive on an eerily silent planet. The Doctor evaluates the planet and discovers that it can sustain life, but it seems to have nothing living on it. This piques his curiosity, and he is keen to investigate this anomaly. Steven is more interested in finding somewhere to swim. Just before they exit the TARDIS the crew discover a small robot feeling its way around the ship before communicating with something else with a glowing antenna. Vicki christens the machines Chumblies. The Doctor deduces that they are blind.

Once the Chumbley has left the TARDIS the Doctor and his companions go out and explore the planet. It has three suns and vegetation but, as yet, no sign of animals. Before they can get far, the Chumbley returns. The Doctor determines that the Chumblies have keen hearing. The Chumbley indicates to the Doctor and his friends that it wants them to follow it. Steven is wary. He tries to attack it. In a show of force, the machine produces a gun from its shell and sets fire to a plant. The Doctor and his companions are led away.

They have not gotten far when a group of women lying in wait for the Chumbley throw a metal mesh on the machine and deactivate it. The women introduce themselves as Drahvins, from the planet Drahva in Galaxy 4. They say that the robots are controlled by a race called the Rills, who are not to be trusted. The Drahvins say that they will take the travellers back to their ship for safety and introduce them to their leader, Maaga. However, when they try to remove the mesh they find it is attached magnetically to the Chumbley. Before they can make their escape, three more Chumblies appear and force the travellers and the Drahvins to flee. The new Chumblies remove the metal mesh from the prone Chumbley, which reactivates itself, and they head off in pursuit of the Doctor.

The exterior of the Drahvin's ship.

The Doctor, his companions and the Drahvins make it to the Drahvin spaceship. Maaga listens to the Drahvins' report, and then reprimands them for the loss of the metal mesh; it was their only weapon against the Chumblies. After Maaga has dismissed the Drahvins, she addresses the Doctor and his companions. She explains that the Drahvins are a powerful race of women warriors who use men only for hunting. They were exploring in this part of the galaxy when their ship was shot down by the Rills though they managed to shoot the Rills down as well. They are desperate to get off the planet because the Rills have informed them that the planet will explode in fourteen days. Their plan is to capture the Rill ship and escape.

Steven is suspicious of the Drahvins. It seems to be they who are in the wrong rather than the Rills. His position is strengthened when Maaga reveals that the Rills have offered help, but the Drahvins have refused for fear of being killed.

This story is interrupted when Chumblies approach the ship. The Drahvins attack them, and the Chumblies deactivate briefly, but then go on their way. Playing on the suspicions that Steven has roused in the Drahvins, the Doctor says that he is a scientist. He will learn if the planet is to explode in a fortnight and see if the Rill have been misleading the Drahvins. The Drahvins agree to this, but demand one of the TARDIS crew stays with them. They insist that this is not a matter of hostages, but to have fewer unaccompanied people wandering the planet. Vicki volunteers to stay and the Doctor reluctantly assents.

When the Doctor and Steven arrive at the TARDIS, they find a Chumbley trying to break the TARDIS's force barrier. Steven and the Doctor hide until the Chumbley leaves. Back at the Drahvin ship, Maaga humiliates the other Drahvins for losing the metal mesh, blaming them for ruining the whole mission.

After unsuccessfully trying to break into the TARDIS, the Chumbley gives up. The Doctor and Steven enter the TARDIS, where the Doctor consults his astral map and finds the planet doesn't have a fortnight until its destruction, as the Drahvins thought. It has only two days; tomorrow is the last day this planet shall see!

Trap of Steel (2)[]

A Chumbley communicates with its masters.

The Doctor and Steven decide they must leave immediately, save Vicki and warn the Drahvins. However, the Chumblies return, this time with heavy explosives. It does no damage to the TARDIS. After they leave, the Doctor and Steven race back to the Drahvin ship. In the Drahvin ship, Vicki is fed up with the food and is worried about her friends. However, Maaga refuses to let her leave.

When Steven and the Doctor get back to the Drahvin ship, Steven points out it is made of a metal that the Chumblies' ray can penetrate. The Doctor ponders why the Chumblies have not destroyed their "enemies". Inside the ship, the Doctor hides the truth from the Drahvin and again tries to convince them to befriend the Rills and work together. Maaga rejects this again. She grows suspicious of the Doctor and pulls a gun on him. Under this threat the Doctor admits they have only two days. He offers to bargain with the Rill for a peace treaty. The Drahvin agree but retain Vicki as an insurance policy. Steven offers himself as a hostage. Vicki and the Doctor leave for the Rill ship.

Steven tries to create disharmony between Maaga and her minions. Maaga overhears this. She tries to convince Steven to pilot the TARDIS with the Drahvin. Steven refuses, saying that even if he wanted to, he doesn't know how. He is left alone and falls asleep.

Trapped by a Chumbley patrol, the Doctor and Vicki are forced to "observe, note, collate and then conclude" their routine. Vicki decides to test a theory by throwing a stone behind the machine. The Doctor is annoyed but she states that she thinks the Chumblies can detect only what is in front of them. They conclude that they can follow one back to the Rill ship rather than wander aimlessly.

Back at the Drahvin ship, Maaga orders her soldiers to break into the Rill spaceship and wipe them out for their ship.

By this time the Doctor and Vicki are at the Rill compound. It has a drilling rig and an air purifier. The Doctor is impressed with the Rills' handiwork. The Doctor and Vicki explore the compound cautiously. Vicki remarks that she can smell ammonia. The closer they get to the compound's centre, the stronger the smell. They arrive in what appears to be a repair shop for Chumblies. As they look around, a large, scaly creature appears at the window. Vicki screams.

Air Lock (3)[]

The Doctor and Vicki try to escape the Rill centre, but they are pursued by two Chumblies. An iron gate then falls; separating the Doctor and Vicki and leaving the latter trapped in the Rill centre. The Doctor decides the best way of disarming the Chumblies is by tinkering with the apparatus that converts the air into ammonia. He assumes the Chumblies need the ammonia. Whilst he wrecks the gas converter, the Chumblies catch up with them and indicate they want Vicki to come with them. The Doctor relents, saying it will give him time to vandalise the converter.

Back at the Drahvin spaceship Maaga shares her frustration with the other Drahvin warriors. She says they are useless at strategy and all they are worried about is killing. If the Doctor and Vicki succeed, she will steal the Rill ship and leave the Rills and the humans on the planet to die. She orders the Drahvins to patrol the perimeter, leaving one to guard the sleeping Steven. She does not know Steven was awake the whole time and has been listening to her.

At the Rill centre, the Chumbley prods Vicki to the window where the creature appears. A voice comes from the Chumbley, telling her that the Rills control the Chumblies. At first, they are hostile to Vicki. However, they learn the Drahvins have been lying to her and tell her the real story.

The two spaceships met above the planet in a standoff that lasted four days. Finally, the Rills tried to leave but the Drahvin ship fired on them. The Rill ship returned fire and both ships crashed.

Steven knocks a Drahvin out.

The Rills tried to speak with the Drahvins. They found an injured Drahvin, whom they tried to help, but Maaga found them and chased them off with a gun; she then killed the wounded Drahvin warrior and blamed the Rills. Vicki realises the Rills are not the enemy. If they cannot bear the planet's atmosphere, the Doctor's tinkering will kill them. She runs to stop him from destroying the gas converter.

At the Drahvin ship, Steven slowly raises himself silently from his bed. He sneaks up to the guard and renders her unconscious. He takes her gun and tries to leave the ship. However, as he goes Maaga comes up behind him. He finds himself facing a Chumbley. He tries to turn back but the Drahvins are pointing their guns at him. He is trapped in the airlock between the ship and the outside. Maaga gives him an ultimatum. He can surrender his gun and return to the ship, face the Chumbley or suffocate as she drains the air from the airlock. Steven is left to think as the air leaves the room.

Vicki gets to the Doctor before he can break the system. Vicki explains the situation to him and they both go to the Rills. The Doctor tells them their escape is at risk. The planet will explode before they expect.

Although the Rill ship is fixed they don't have enough fuel. The Doctor says he can help them with metal cord cable and a sort of jump lead that he has in his TARDIS. The Rills are happy to hear this, but the Chumbley outside the Drahvin spaceship tells them Steven is in danger. The Doctor and Vicki rush to his aid with two Chumblies. They are stopped by a Drahvin warrior who thinks that the Doctor has betrayed them. Vicki tries to convince the warrior that the Chumblies are under their control. The warrior tries to shoot the Chumbley, but Vicki disarms her. The Drahvin begs to be killed for her failure. The Doctor says no one will be dying on this planet any time soon.

At the spaceship, Steven decides he would rather face the Chumbley than return to the Drahvins. He tries the door but it cannot be opened. Steven struggles for breath.

The Exploding Planet (4)[]

There is no time to spare. A Chumbley shoots an ammonia bomb into the Drahvin spaceship and fires its weapon at the airlock, freeing Steven. The Drahvins flee and are met by a horde of Chumblies. The Rill tells them for all these years, they have been pacifist in their dealings with the Drahvin. Now that they have threatened to kill Steven, they will be killed in return. The Rill orders the Drahvins back into their ship. If they are seen on the planet's surface again they will be killed.

Inside the ship, Maaga blames the Drahvin who was on patrol for their predicament. She will pay the ultimate price when they have more time. Maaga lays out her plan to destroy the Rill ship.

The Doctor with a power cable to help the Rills.

In the Rill ship, the Doctor puts the finishing touches to his plan to give a jump start to the ship's engine with his TARDIS. He leaves Steven to recover in the Rill centre whilst he and Vicki return to the TARDIS to link it to the Rill ship's engine. Alone with the Rill, Steven expresses his doubts about the benevolence of the Rills. He suspects that if the Doctor cannot fix their ship the Rills will not let them go. The Rills say they would let the Doctor go. They have no knowledge of conflict and would rather have a life saved than kill someone for no reason. Steven apologises for his scepticism. On the other side of the planet, one of the Drahvins sneaks up behind the Chumbley guard and destroys it.

The Rill is told the Doctor has hooked up his TARDIS. Steven is nervous. He is sure the ship will not be powered up in time. The Doctor and the Rill assure him they can complete the process before the planet explodes. A Drahvin burst into the Rill centre. Before she can do any damage, a Chumbley paralyses her.

In the aftermath, Steven and Vicki look for the Doctor. They find him in the section of the Rill centre with the Rill, where they were not allowed before. The Doctor invites them in, and the Rill gives them permission to enter. At first, shocked at their ugliness, the humans come to an understanding with the Rill. They bid each other farewell.

Meanwhile, the Drahvins wait outside the Rill camp. They fight off an army of Chumblies to get close to the Rill ship. They find that their weapons are useless and decide to rush the ship.

With the ship ready for flight, the Rill sends a Chumbley to escort the Doctor and his companions to the TARDIS. The TARDIS travellers watch as the Rill ship flies off. Nearby, the Drahvins despair as their chance of salvation disappears into orbit. Maaga catches sight of the Doctor and his companions. The Drahvins pursue them to hijack the TARDIS, but it dematerialises before the Drahvins reach their door. Seconds later the planet explodes, destroying the Drahvin soldiers and Maaga.

Back on their travels, the Doctor and his companions lament that they have had precious little time for peace and quiet recently. Vicki looks at a planet below and wonders what might be going on there.

On that planet, unbeknownst to the travellers, an astronaut named Garvey has awakened in a dense jungle, remembering only that he "must kill"...


Uncredited roles[]


Uncredited crew[]

Animation Team[]

  • Animation by Digitoonz Media & Entertainment PVT Ltd
  • Studio Head - Prashant Kumar
  • Animation Director - Ayan Banerjee
  • Animation Supervisor - Souvik Nandi
  • Design Supervisor - Sandip Dutta
  • Animatic Supervision - Biman Mohanta
  • Background Supervisors
    • Prasanta Bose
    • Satendre Singh
  • Project Coordinators
    • Neetu Choudhary
    • Khushboo Kumar
    • Madhumita Bera
  • Project Manager - Isha Sharma
  • Production Coordinator (Rig & Background) - Manish Tripathi
  • Rig Supervisors
    • Goopal Nath
    • Bidhu Bhushan
  • Pre-Composition
    • Shashikant Kumar
    • Raghav Khurana
  • Head of Production - Mantosh Kumar
  • CEO/Founder - Vikas Kumar
  • Post-Production Editing, Compositing & Grading by Thaumaturgy
  • Head of Studio - David Devjak
  • Technical Director - Conor Hodder
  • Post-Production Coordination - Adam Boys
  • Compositors
    • Chris Downey
    • Hannah Lyn Walker
    • Michael Puglisi
  • Sound Restoration & Mastering - Mark Ayres
  • With thanks to David Holman & Allen Wilson
  • Opening Titles & 3D Tardis Exteriors - Rob Ritchie
  • 3D Tardis Interiors - Daniel Pham
  • Additional 3D Modelling - Matt Umney
  • Concept Designer - Ioan Morris
  • Script Supervisor - Mark B. Oliver
  • Associate Producer - Damian Shanahan
  • QAR - The Ark
  • Business & Legal Affairs - Linda Duncan
  • Production Finance - Aisha Bhatti
  • Consumer Products - Fiona Ball
  • Produced & Directed by Chloe Grech
  • Executive Producers for Big Finish Creative
  • Executive Producer for BBC Studios - Russell Minton


Story notes[]

A publicity still showing Drahvins and Chumblies fighting side by side

  • The working title for this story was The Chumblies. (REF: The First Doctor Handbook)
  • Only the third episode of this four-part story, "Air Lock", exists in the BBC Archives as a 16mm black & white film telerecording. However, this is an incomplete print; due to a break in the film, it is missing both the last twenty-seven seconds of action and the closing credits.
  • The continuity from this story runs through until The Daleks' Master Plan. At the end of "The Exploding Planet", Vicki complains of a sprained ankle. As she contemplates the planet Kembel on the scanner, there is a short scene with Garvey as he begins his transformation into a Varga plant. Garvey as a Varga later threatens Cory and Lowery in Mission to the Unknown. When we next see the TARDIS at the beginning of The Myth Makers, Vicki's ankle is still hurting. Finally, after taking off at the conclusion of The Myth Makers, the Doctor discovers Cory's tape on Kembel during the first episode of The Daleks' Master Plan. Mission to the Unknown thus presents an unusual example of the story-to-story narrative flow that was common-place in the Hartnell era.
  • Mervyn Pinfield was originally hired to direct. Unfortunately, as work progressed, Pinfield was taken ill and was unable to continue. Derek Martinus replaced him. This was subsequently Pinfield's last contribution to the programme. He passed away on 20 May 1966.
  • Maaga was originally named Gar, but was renamed when the Drahvins were changed to female characters.
  • This story has the distinction of being the only non-Dalek story to use the "heartbeat" background effect (heard in Rill centre scenes) used in Dalek stories of this period and thus associated with them.
  • This is Derek Martinus' only Doctor Who story not to feature any of the Doctor's iconic enemies. All of his remaining stories featured either Daleks, Cybermen, Ice Warriors or Autons.
  • The stars greatly disliked the scripts for this serial. Things got so heated that John Wiles threatened to fire William Hartnell. Maureen O'Brien's complaints led to Wiles not renewing her contract beyond its expiry during The Myth Makers, and thus she departed from the show.[6]
  • All four episodes of this story were thought lost, with only very limited material held in the BBC archive. "Air Lock" was recovered in July 2011,[7] and its return was announced on 11 December 2011.[2]
  • Robert Cartland replaced Anthony Paul.
  • Six minutes of footage exists from "Four Hundred Dawns". The surviving clips come from a number of sources, including a Lively Arts documentary Whose Doctor Who.
  • Ian Levine claimed that the Doctor Who Appreciation Society obtained legal permission to screen this serial at a convention privately in 1978, only to find that the BBC had junked the episodes about three weeks earlier.[8] Later research showed this to be mistaken. The DWAS never had any agreement to show the serial and BBC Enterprises appear to have junked at least one of the episodes by the end of 1976.[9]

One of two known publicity stills featuring a Rill.[10]

  • The soundtrack for the serial is intact and has been released commercially by BBC Audio with linking narration provided by Peter Purves.
  • The BBC partly own the rights to the Drahvins as they were jointly credited to William Emms and Verity Lambert. Emms created the (originally male) Drahvins, whilst Lambert made them female.
  • The stock music used for the soundtrack was performed by an experimental group called Les Structures Sonorés. They performed their music on glass tubes. Some of the same music was used in The Web Planet.
  • William Emms had been a fan of the show since the start and submitted the idea in early 1965.
  • Derek Martinus had never seen the series before and was shown some old episodes. He was disappointed and wanted to aim for higher standards.
  • Stephanie Bidmead took Maaga’s prop pistol as a keepsake for her son to play with.[11]
  • This marks the thirteenth incomplete Doctor Who serial to be animated (excluding Shada) but only the third of the Hartnell era. The other two being The Reign of Terror and The Tenth Planet which were both released in 2013.
  • The animated release of this serial makes Derek Martinus the first Doctor Who director to have all his lost episodes reconstructed in animated format (excluding directors who only have one serial that's missing episodes).

Changes in the animated version[]

  • Vicki's outfit is plain rather than patterned (this is because the patterns shift whenever Vicki moves and that would have been too complex to animate).
  • With the exception of Maaga, all the Drahvins are identical.
  • The Chumblies arms are retractable and more flexible.
  • The interior of the Rills ship is a lot bigger.
  • The space battle between the Drahvins and the Rills is shown.
  • Maaga kills Drahvin Four using her pistol.
  • The Chumblies use their arms to communicate with the Rills rather than their aerials.
  • The Rills' viewing window is smaller and is built into a triangular shaped structure.
  • The Chumblies in the "repair shop" are each in their own little "port".
  • In "Air Lock", the Rill does not appear in the viewing window, instead remaining hidden behind a cloud of smoke.


  • "Four Hundred Dawns" - 9.0 million viewers
  • "Trap of Steel" - 9.5 million viewers
  • "Air Lock" - 11.3 million viewers
  • "The Exploding Planet" - 9.9 million viewers


  • The Drahvins' costumes were green in colour, despite official depictions since.[12] (It is Peter Purves's recollection that they were indeed blue.)[13]
  • A late change to the casting of the voice actor meant that Anthony Paul was credited in Radio Times as providing the Rill Voice for "Air Lock". (Robert Cartland was correctly named in Radio Times.)
  • William Emms was a school teacher who wrote in his spare time. (Although he had been a school teacher, he had been working as a full-time writer for four years before writing for Doctor Who.)

Filming locations[]

All episodes were filmed at BBC Television Centre TC4, London, UK

Production errors[]

If you'd like to talk about narrative problems with this story — like plot holes and things that seem to contradict other stories — please go to this episode's discontinuity discussion.
Original Production[]
  • In "Four Hundred Dawns", just after Maaga first mentions the Rills, the camera shakes slightly.
  • When the Doctor is tampering with the air converter, a Chumbley approaches Vicki on her right-hand side and sits motionless for a few moments.
  • When the Chumblies return Vicki to the Rill command centre, an inert Chumbley can be seen next to her. But when the camera switches angles, the Chumbley is suddenly active.
  • In "Air Lock", the Rill centre electronic effect is heard throughout the scene where Steven attempts to escape from the Drahvin ship.
  • When the Doctor and Vicki are walking through the Rill command centre, the shadow of a camera is briefly visible on a column.
  • William Hartnell flubs a line in "Air Lock", when he begins to say "I wust..." before correcting himself to "I must have that conversion".
  • In "Air Lock", the Rill twice refers to the Chumblies as "Crumblies."
Animated Version[]
  • In "Four Hundred Dawns" when the Doctor and Steven are trying to get back into the TARDIS, two Chumblies are outside, one very close to the TARDIS and the other slightly to the right. But in the next, closer up, shot, the second Chumbley appears on the left.


Home video and audio releases[]

Video Release[]

  • A six-minute clip appears in the documentary The Missing Years, part of The Ice Warriors VHS box set.

DVD releases[]

  • On Disc 1 of the Lost in Time DVD box set there is an 8mm off-air clip, while Disc 3 contains a six-minute clip in an updated version of the documentary The Missing Years.
  • The BBC have recovered the third episode, "Air Lock". This episode was remastered and released on DVD alongside the special edition of The Aztecs on 11 March 2013.
  • A reconstruction of this story has been made using the available images and audio by Loose Cannon Productions.
  • The animated version, with both a black-and-white and a colour version of the story, was released on DVD in the UK on 15 November 2021. Additionally a Blu-ray and Steelbook edition was released in the UK simultaneously with the respective DVD release. Separate DVD editions and Blu-ray editions were both scheduled to be released in Australia on 12 January 2022.


    • Commentary (surviving episode 1 clip & surviving episode 3) with actors Peter Purves (Steven), Maureen O'Brien (Vicki) and Lyn Ashley (Drahvin Four).
    • Commentary (episode 1) with actors Peter Purves and Maureen O'Brien.
    • Commentary (episode 1) with Animation Co-Executive Producer Gary Russell.
    • Commentary (episode 2) with Vision Mixer Clive Doig and Special Sounds Designer Brian Hodgson.
    • Commentary (animated episode 3) with Assistant Floor Manager Sue Willis.
    • Commentary (episode 4) with actors Peter Purves, Maureen O'Brien and Lyn Ashley.
    • Commentary (episode 4) with animation Producer/Director Chloe Grech. All moderated by Toby Hadoke.
    • The Trouble with Chumblies - Making Galaxy 4, making of documentary for the original production.
    • Finding Galaxy 4, the recovery of the episode 1 clip and episode 3 featuring Terry Burnett, Ralph Montagu and Jan Vincent-Rudzki.
    • Episode Reconstructions.
    • Teaser Trailer.
    • Production Subtitles.
    • Photo Gallery.
    • Script PDFs
    • Radio Times Listings

Audio releases[]

Script book[]

  • In July 1994, Titan Books published the scripts for the serial as part of its Doctor Who: The Scripts line of books.

External links[]