Professor Zaroff shoots King Thous and orders the deaths of his guards, before declaring that nothing in the world can now stop him. He then marches off to his laboratory.
The Doctor and Ben arrive soon after and find that Thous is still alive, though badly wounded. They take him to the secret chamber behind the temple.
There, the Doctor learns that Jamie and Polly have gone off to the laboratory in search of him. He has devised a plan - one which carries huge risks. He and Ben will go to the power generating station and create an overload. It should cause the sea wall to breach, resulting in the lowermost levels of Atlantis being flooded. This would include Zaroff's laboratory but also cover the temple precinct. The Doctor cannot guarantee where the water level will settle, so asks Sean and Jacko to go round the city to warn the inhabitants to make for the uppermost levels.
Ara will tend to Thous.
In his lab, Zaroff is preparing for the culmination of his plans, but the technicians in the various substations begin to panic as they hear of the growing food shortages. Even calling upon guards to help, Zaroff realises that his project could be at risk but he is determined to carry on.
The Doctor and Ben arrive at the generating station and find an armed guard on duty, who expects a password. Ben pretends to be escorting the Doctor as his prisoner, and between them they manage to bamboozle the guard into giving away the password and they gain entry.
They knock out the technician and the Doctor sets the overload building.
Elsewhere, Jamie and Polly have become lost in the tunnels. They see one of the rock walls glow and begin to crumble. Sea water begins to flood in.
Ara is helped by Sean and Jacko to get Thous up to a higher level of the city. They meet Damon, who tells them that his operating theatre is now submerged. The temple also floods, and Lolem has perished after refusing to abandon it.
They are forced further up through the city, and emerge onto the outside of the volcanic mountain. Damon's people are setting up a refugee centre here.
The Doctor and Ben go to the laboratory to confront Zaroff. He refuses to surrender and lets down a heavy metal gate, sealing him in the section of the room which contains a plunger which will trigger the explosion that will split the Earth in two.
Jamie and Polly manage to exit the city onto the surface.
As water rushes into the lab, Ben leaves - urging the Doctor to abandon Zaroff to his fate. The Doctor instead tricks the scientist into opening the gate after turning off the lights, closing it again so that the scientist is cut off from the trigger device.
He urges Zaroff to come with him. The crazed scientist refuses and is drowned.
Out on the surface, the Doctor reunites with his companions.
Thous and Damon discuss the rebuilding of Atlantis but the latter insists that there must be no more superstition, as it was this which Zaroff had exploited, and there must be no more Fish People either.
Sean and Jacko are surprised to see the Doctor and his companions enter a Police Box, which suddenly vanishes.
Jamie asks where they will be going next, only to be told by Ben and Polly that the Doctor has no control over the TARDIS. Annoyed, the Doctor insists that he will take them exactly where they want to go to prove his mastery over the ship. The planet Mars is suggested, but as soon as the Doctor sets the controls the TARDIS begins to lurch violently out of control...
Next time: The Moonbase
Data:Written by Geoffrey Orme
Recorded: Saturday 28th January 1967 - Riverside Studio 1
First broadcast: 5:50pm, Saturday 4th February 1967
Ratings: 7.0 million / AI 47
Designer: Jack Robinson
Director: Julia Smith
Additional cast: Ralph Watson (Technical overseer / technician voice)
Critique:Atlantis - the Island of Atlas - is first mentioned by Plato in his 4th Century BC works Timaeus and Critias. It's described as a great naval power, dominating the western half of the known world. After falling foul of the gods, they caused it to sink beneath the surface of the Atlantic Ocean. It was very much presented as an ideal society and so regarded as an allegorical city state rather than a real historical place, despite physical descriptions such as its position beyond the Pillars of Hercules (the Straits of Gibraltar) and its layout of a series of concentric islands separated by canals.
Later writers such as Francis Bacon and Thomas More incorporated it into their work on utopian societies. However, in more recent times writers began to write of it as having been an actual civilisation. This had been technologically far in advance of known ancient civilisations, and it was claimed that it had been refugees from Atlantis who had passed on their knowledge to the peoples of the Middle East, South America etc. Inevitably, Atlantis was also linked with aliens, having been established by them in the first place.
Some archaeologists have searched for evidence of Atlantis, but either as a city on the western edge of Europe or North Africa which has since fallen into the sea, or as one of the ancient civilisations of the Mediterranean or Aegean regions. Others are looking further west in the Caribbean region.
One theory popular in recent years is that Atlantis was based on the Minoan civilisation centred on Crete. This was devastated by a tsunami created by the eruption of the Thera volcano (Santorini). The eruption was so explosive that Thera was left as a circular island with the core of the volcano at its heart - giving the concentric ring description given by Plato.
This particular theory found its way into Doctor Who in 1972, in the story The Time Monster. The final two instalments of this six-parter see the action shift to Atlantis.
The design team look to the Minoans for sets, make-up and costumes whilst the ancient volcanic eruption of Thera is specifically mentioned in dialogue in the first episode.
The story sees the city destroyed around 1500BC by the Chronovore Kronos, angered by its lengthy imprisonment by the Atlanteans.
Exactly one year before, and from the same writers, we had The Daemons. This stated that it was the titular creatures who had destroyed Atlantis when it was deemed a failed experiment.
The Underwater Menace does not give any detail at all about the ancient destruction of Atlantis - only that there were survivors who carried on the civilisation in the subterranean levels of their volcanic island. So it could have been destroyed by Azal, or it could have been destroyed by Kronos, but can it be both?
Fans have, naturally, tried to square this particular circle by claiming that The Daemons and The Time Monster don't necessarily depict the same event. The city is sunk by Azal / Kronos but survivors are able to re-establish it - only for this New Atlantis to then be wrecked as well, not long after.
Jump forward to 2015 and it is mentioned in The Magician's Apprentice that there is a strong temporal paradox centred on Atlantis - so all three stories simply co-exist.
Episode 4 sees more of the filming at Winspit Caves, located near Worth Maltravers in Dorset. Filming there on Monday 12th and Tuesday 13th December had been for the first and fourth instalments, covering the arrival and the departure of the time-travellers on the island. For this final episode, the regulars had to change their costumes. Patrick Troughton discarded his hat and cloak, whilst Michael Craze and Frazer Hines donned wetsuits. Anneke Wills had to wear the uncomfortable Atlantean dress for the first time.
PG Stephens and Paul Anil were in attendance to film their final scene of the story as Sean and Jacko witnessed the TARDIS departure.
Thous, Damon and Ara also appear outside the city at the conclusion of the episode, but their scenes were set in a cave mouth and were recorded in studio.
Filming continued at Ealing from Wednesday 14th December. This included the glowing rock wall observed by Jamie and Polly, which then crumbles as water pours through. A model of the temple was also filmed flooded. This included shots of water pouring through the idol's eyes and mouth.
Live action filming centred on the climactic scenes in Zaroff's laboratory. This set had been constructed in the studio's water tank, which was then slowly filled. The first shots recorded saw the water begin to gush in around the professor. Next were shots of him trying to reach through the bars of the metal grille, and his head going under. The final shots were of loose items floating in the water after the scientist has drowned - including the plunger device. As the tank filled so slowly, there were lengthy gaps in the filming before shots could be captured.
Since studio recording had moved from Fridays to Saturdays rehearsals had always begun on a Tuesday, but this week they began a day early - on Monday 23rd December.
That Friday Troughton was issued with a new contract for 23 episodes, covering four new stories. Michael Craze received his for 10 episodes - which would take him up to the second instalment of the next Dalek story planned.
Unusually the final episode was recorded out of sequence. The closing TARDIS scene had been a late addition to the scripts, and this was recorded first. A rotating camera lens was employed to add to the effect of the ship being out of control. Closing credit captions came next, and after a short break the evening saw recording run in story order.
The opening credits were played over close-up shots of Zaroff's gun and his face. The next break came when Hines and Wills moved to the rock tunnel set, where they witnessed the collapsing sea wall, with a third just before the Doctor decided to return to the lab to try to save Zaroff.
Ralph Watson appeared on a TV monitor on the laboratory set, and also provided the voices of other technicians reporting from other substations.
Zaroff's countdown clock was actually the Rel Counter, seen recently in Daleks: Invasion Earth - 2150AD.
The generating station set was a new one, and featured a large working cog-wheel. It was linked directly to the corridor set where the guard was stationed, to allow continuous recording.
As mentioned, Thous, Damon and Ara were seen only in studio for their final scenes, using the same set which had featured as the rocky tunnel traversed by Jamie and Polly.
One scene was deleted from this sequence before broadcast, in which Sean and Ara were adamant that the Doctor survived after Jacko was convinced he must have drowned.
The problem of too many companions is evident in this episode, as Polly and Jamie are basically sent up a cul-de-sac - literally. With no role for either, they wander about some tunnels for much of the time. Presumably Polly would have been used to help Ara and Thous before Jamie was introduced and needed something to do.
The story may be poorly regarded overall, but it does have its moments - including the sequence in this episode where Ben and the Doctor trick the generating station guard, with some lovely dialogue.
Ben: "A guard! How are we going to get past him?"
Doctor: "We'll walk past him".
Ben: "In those trousers?"
We also have:
Guard, referring to the Doctor: "How do I know he's a wanted man?"
Ben: "Well, blimey, look at him. He ain't normal. is he?"
The Doctor then accuses the guard of not knowing the password himself, so he blurts it out to them.
William Hartnell noticeably raised his game when he had to act against a strong guest artist, someone who would make him have to work. Something similar seems to happen here, as Troughton comes up against Joseph Furst's OTT performance. It is noticeable that Troughton gives a more subdued performance opposite him, and there is less overt clowning in comparison with previous story. There's no point competing with Furst, so Troughton dials his performance back.
Only one brief clip survives from this episode - a shot of Professor Zaroff about to drown in his laboratory, cut by the Australian censor.
Not many countries bought this story - typical of Season 4. Australia took it first in 1967, when the censorship action took place prior to screening in September and October of that year. New Zealand took it in 1969, as did Hong Kong and Singapore. A year later it was bought by Zambia.
The 405-line videotapes for this episode were cleared for wiping in September 1969.
Trivia:- The ratings have fallen by 1.3 million between first and last episodes of this serial.
- This was the shortest of the four instalments, at only 23' 20". The second episode was the longest at 25 minutes.
- This episode proves to be the final sighting of the Doctor's tall Paris Beau hat, worn by Polly in the closing TARDIS scene. Troughton's friends had advised him to ditch it, and it was dropped as part of a small but significant revision to the character. The disguises and a lot of the more overt clowning were discarded, and the darker, more manipulative Second Doctor begins with the following serial.
- Ralph Watson will return in The Web of Fear to play Captain Knight, and later portraying Ettis in The Monster of Peladon, and Ben in Horror of Fang Rock.
- There is a suggestion that the Twelfth Doctor and Clara encountered Fish People in dialogue from the start of The Caretaker.
- The story was due to have its missing episodes animated back in 2012 but the company went bust. The story finally came out on DVD / Blu-ray with animated episodes in time for the 60th Anniversary. The team behind the animations took the opportunity to reimagine all of the visual elements beyond the TARDIS and the time-travellers. As such, they don't match the existing material in any way - so it's pointless watching them if you wish to enjoy the original episodes - and most of the new designs are very poor anyway. The Fish People are especially badly realised.
- And finally, another great retro-style film poster from artist Oliver Arkinstall-Jones:
