The Underwater Menace ( TV story ) The Underwater Menace was the fifth story of season 4 of " Doctor Who " . , its second episode is the earliest surviving Second Doctor telerecording . Currently , only episodes two and three survive in full . Synopsis . The TARDIS arrives on an extinct volcanic island . Before long , the travellers are captured and taken into the depths of the Earth , where they find a hidden civilisation — the lost city of Atlantis . The Atlanteans worship a goddess named Amdo and use fish people — men and women operated upon so that they can breathe under the sea — to farm the plankton - based food on which they survive . A deranged scientist , Professor Zaroff , has convinced them that he can raise their city from the sea , but actually he plans to drain the ocean into the Earth ' s molten core , so that the resultant superheated steam will cause the planet to explode . The travellers meet up with two shipwreck survivors , Sean and Jacko , who persuade the fish people to rebel and stop work . The Doctor eventually foils Zaroff ' s plan , but only by breaking down the sea walls and flooding the city . Zaroff drowns , but everyone else escapes . Plot . Episode 1 . Jamie is blown away by the interior and the workings of the TARDIS . The Doctor quotes Robert Burns to him — which confuses him further due to the fact that Burns wouldn ' t be born until ten years after Jamie was taken . The TARDIS materialises on a volcanic island . The crew explore their surroundings ; Ben , Polly and Jamie climb up a shallow hill for a better vantage whilst the Doctor begins to investigate the rocks to give him a clue as to their whereabouts . As the three companions climb , Polly thinks she sees something in the distance , but Ben and Jamie say she must be imagining it . Polly decides to wait for the boys as she is running out of breath . They leave her on a ledge to return for her when they reach the top . She begins to explore and finds a bracelet that she examines very closely before beginning to explore in a nearby cave . Here she is confronted by robed figures . She screams , which alerts Jamie and Ben . They return back to the cave and begin to explore . They are ambushed by the robed figures who capture them and put them in a small room where Polly is tied up . They discuss what to do until the door opens again and the Doctor is thrown in with them . Once all four are together , the room begins to descend like an elevator . The companions suffer difficulty in breathing , nausea and a strange taste in their mouths before they fall unconscious . They awake later in a compression chamber . The Doctor wonders when they are . Polly takes a stab at the 1970 s . When challenged she reveals the bracelet which is a souvenir from the 1968 Olympics in Mexico , alluding to the fact that it must be some point after that . A guard armed with a spear enters . Polly and Jamie try to communicate with him but to no avail . He gesticulates with his spear , indicating that they should go down a corridor . They are taken to a dining hall and given a dinner of plankton . The armed guard is hostile towards a serving girl called Ara , for whom the Doctor sticks up . Lolem , a priest , arrives and says that their goddess Amdo prophesied visitors falling from the sky before one of their festivals . He orders his guards to seize the four travellers in preparation for their sacrifice . As they are dragged away , the Doctor says he has something important he needs to say . Lolem humours him and says he has five minutes whilst his friends are dragged away . The Doctor says that Professor Zaroff , who he has deduce d to be there , would be very disappointed if he heard that Lolem had killed him . When questioned as to how he knew Zaroff was there , the Doctor states that only he could produce such delicious food from plankton . Lolem says that this changes nothing and that the Doctor will still die . The Doctor asks for him to send a note to Zaroff . Lolem forbids this , but the Doctor smuggles the note to Ara and asks her to deliver it . The companions have been led into a temple surrounded by a moat of shark - infested water . Ben , Polly and Jamie are tied up and placed on ramps that tilt into the water . The Doctor is led into the temple , tied up and placed on the fourth ramp . The ramps slowly begin to lift . The four victims try to cling on as best they can . Ara goes to Zaroff ' s quarters and is forbidden entry . She then asks to see someone called Damon . Damon is given the note which reads , " Vital secret will die with me . Dr . W . " Damon immediately gives the note to Zaroff , who rushes out and stops the ceremony and orders the Doctor to be released . Initially his companions are to be consigned to their fate , but the Doctor tells Zaroff that he will not tell his secret whilst his friends are in danger . They are sent to the labour controller . Zaroff and the Doctor speak privately . It is revealed that Zaroff faked his own death , allowing the world to think he was assassinated or kidnapped in a plot between East and West Germany . The Doctor flatters him so much that when he admits that he has no secret , Zaroff praises him for his sense of humour and allows him to live . Damon is in charge of the labour and sends Jamie and Ben to the mines . When left alone with Polly , he slightly intimidates her before showing her Zaroff ' s plans . Outside are farmer s who have been given plastic gills in order to farm food under the water . Polly marvels at this but blanches when she discovers that this is the fate that Damon has in mind for Polly . The Doctor and Zaroff talk and the Doctor deduce s that they are in the lost city of Atlantis . Zaroff reveals that , in return for raising Atlantis , he was allowed to practice his experiments in the city . Ara comes and informs the Doctor of Damon ' s plans for Polly . The Doctor tells Ara to go back to Polly , watch over her and , if she has a chance , to get her away from Damon . However , it seems too late as Polly is on the cusp of being anaesthetised by Damon . Episode 2 . Whilst being shown round a laboratory , the Doctor fiddles with the lighting , which affects the operating room . This stalls the procedure . Damon storms up to the laboratory , demanding to know why Zaroff is draining so much power . Zaroff shows Damon he has a separate generator . Whilst the two argue , the Doctor fuses the generator , plunging the operating room into darkness . The two doctors leave Polly to see what is going on . Ara sneaks in and frees Polly — taking her to the caves . Damon is furious with the Doctor , and even Zaroff agrees it is best if the Doctor stays with him . Zaroff explains his plan to the Doctor . He plans to core into the centre of the Earth and drain the water away so as to render Atlantis accessible by land . The Doctor realises it will blow the planet apart and Zaroff concedes that this is an issue , before stating that will be his final testament . Down in the mines , Ben and Jamie meet Sean and Jacko . They are immediately ingratiated into their gang when Jamie helps them hide a compass from the dictatorial foreman . They explain that they are going to use a compass for a break out plan . The Doctor discovers that Polly has been freed and escapes from Zaroff ' s lab by creating a chemical reaction that causes a stultifying effect on those that breathe in the fumes . Sean and Jacko explain that they have found an underground shaft which they will use to escape . Ben and Jamie will join them . An alarm sounds in the mine , which means the group is going to separate . The four decide to slip away in this process . The Doctor has sneaked into the cave system . He encounters Ara , who tells him Polly is safe . While they talk they overhear a priest called Ramo talking to Damon . The Doctor discovers that Ramo also mistrusts Zaroff . The Doctor asks Ara to distract Damon so he can talk to Ramo privately . Ara approaches Damon and tells him that she saw Polly in the marketplace . Damon falls for it , and the Doctor approaches Ramo . He goes to call out , but the Doctor convinces him that he has important information regarding Zaroff . They go somewhere private to discuss . The party of escapees decide to split up to find the best way through the mines . At the temple , the Doctor shows Ramo what Zaroff intends to do using a jug and a fire as props . Ramo is convinced and says he will summon him to an audience with the supreme leader Thous but warns the Doctor that Thous is a strong advocate of Zaroff ' s . Jacko joins up with Sean and Ben to say that Jamie has slipped down a cliff edge . Sean goes on to see if there is a better means of escape while Sean and Ben go back to help Jamie . Back at the temple Ramo gives the Doctor some ceremonial robes in order to get him close to Thous . As soon as they leave , Polly leaves from her hiding place . As she does , a secret door in the temple opens and Ben , Jamie , Sean and Jacko emerge . Once alone , the Doctor and Ramo explain Zaroff ' s plan to Thous . He asks to be left alone to consider his options . Ara returns to feed the refugees but is interrupted by people entering the temple . Everyone except Ara hides in the secret compartment . The Doctor and Ramo are summoned to the temple . Thous said he has considered both their opinions . Just then , Zaroff and his guards enter . Thous tells Zaroff to do with them what he will . Episode 3 . The Doctor tries to protect Ramo by telling them that he was led astray by him , but Ramo stands up for himself and states he has always hated and mistrusted Zaroff . The Doctor and Ramo are led away to be fed to the shark s . When left alone with Thous , Zaroff promises him that the Doctor ' s stories were untrue . The Doctor and Ramo are brought by Lolem , the high priest , and the priests to the idol of Amdo , about to be beheaded as a sacrifice and fed to the sharks when a voice issues from the statue of Amdo , commanding all present to bow their heads . The Doctor , recognising the voice as Polly ' s , escapes with Ramo and meets up with his friends in the secret enclave in the temple . On rising from their prayer and finding the Doctor and Ramo gone , Lolem claims it to be a miracle . The statue has a mouthpiece on the inside designed for people to sound like their words are emanating from the idol . Zaroff tells Thous that his plans will come to fruition in two days ' time . Lolem enters and tells Zaroff and Thous of the " miracle " . Zaroff is scathing of Lolem ' s stupidity and orders Atlantis searched despite the doubts of Thous . Inside the idol the Doctor makes his plans : Sean and Jacko will convince the fish people to stop supplying the perishable plankton to Atlantis , and the rest will kidnap Zaroff . The Doctor and Polly disguise themselves as regular Atlantis shoppers in the marketplace whilst Jamie and Ben disguise themselves as guards . Avoiding the real guards , the four of them trick Zaroff away from his guards and into the temple where he is captured . Meanwhile , Sean insults the fish people until they are in such a state of disarray that they agree to stop production to get back at Zaroff , the man Sean blames for their current state of servitude . Zaroff taunts the Doctor , saying that without him the plan will still go ahead . The Doctor doubts this , stating that Zaroff ' s egomaniacal ways would stand in the way of such a hands off approach . Zaroff becomes enraged by this and falls into a fit . The Doctor takes Ben and Jamie to the laboratory to check on Zaroff ' s progress while Polly and Ramo guard Zaroff . A service is going on outside , so the Doctor and his companions hide until it is finished . Inside the idol Zaroff repents his behaviour and begs Ramo to help him up so he can pray with him . Ramo consents after convincing from Polly . This is a trick , and a scuffle breaks out between the two . Eventually Zaroff stabs Ramo and disappears into the cave system with Polly as his hostage . Once the service has finished , the Doctor decides Jamie should go back and ask Ramo for directions . As he turns back , he meets the mortally injured Ramo , who mutters about Polly ' s abduction before dying . The Doctor sends Jamie after Polly whilst he and Ben go on to the laboratory . Jamie catches up with Polly and overpowers Zaroff . A fight breaks out between them . Zaroff appears to have the upper hand when Sean and Jacko join the fight . Zaroff runs off into the cave system . Polly decides they need Ara to help reunite them the Doctor . Back at the council chamber , Thous is informed by Damon of the revolt of the fish people . He agrees to enter discussions with them . Zaroff enters and overrules this , saying that any dissenting fish people will be killed . Thous says he has no right to overrule him and attempts to arrest Zaroff . Zaroff shoots Thous . Zaroff then orders his two guards to kill Thous ' guards — which they do . He then vows that nothing in the world can stop him now . Episode 4 . The Doctor and Ben discover the bodies left by Zaroff . The two guards are dead , but Thous is wounded . They decide to take him back to the temple . Jacko and Sean are unsure as to what to do — they are tempted to leave the Doctor to it . The Doctor returns with Thous and announces his plans . He informs them he is to flood Atlantis to stop Zaroff . He orders Jacko and Sean to move the people while he and Ben will begin the process . Zaroff hears that workers are leaving their post due to the shortage of food — they are having to go and scavenge their own food . Ben and the Doctor sneak into the generating station by Ben , dressed as a guard , pretending that the Doctor is his prisoner . Once inside , they knock out the scientist and make the reactor overload before heading off to Zaroff ' s laboratory . Lost in the cave system , Jamie and Polly see one of the cave walls glowing luminously due to the radiation . As the wall begins to degrade , water begins to flood in . The pair need to make it to land , but the path they choose leads to a dead end . Jacko and Sean hear the noise and decide it ' s time to leave . Damon joins their gang , lamenting the ruination of his life ' s work . As they escape , the temple is destroyed . Thous is distressed that Lolem was in there , but they are forced to push on . Zaroff , concerned by the fluctuations caused by the Doctor , brings the mission forward . It will commence in five minutes . The Doctor enters and explains to the technicians and guards Zaroff ' s true plan . They desert him . Zaroff locks himself into his laboratory , saying that the Doctor and Ben will never get to him . As time passes , Ben hears the sea approaching and makes to leave . In order to make life harder for Zaroff , the Doctor cuts off his light supply . Zaroff comes out from his laboratory , armed , to switch the lights back on . Ben returns and locks Zaroff in his own laboratory , allowing Ben and the Doctor to escape . The Doctor wants to go back to save Zaroff , but there is a rockfall blocking the way to the laboratory . The water rises in Zaroff ' s laboratory . As the dial on his experiment drops to zero , he descends into the water . In the cave , Polly and Jamie reach a ledge and Polly gives up , but Jamie convinces Polly to continue climbing up . Soon enough they reach the surface . Jamie breaks it to Polly that it is unlikely the Doctor and Ben have survived . Also safe , Ara , Thous and Damon think the Doctor dead . Thous wants to raise a stone for him in the new temple , but Damon says there will be no temples in the new Atlantis . As Ben and the Doctor make their way up to the land , Ben wonders if Polly has survived . On land , Polly and Jamie sit disconsolate , until the Doctor and Ben emerge from the ground . They head to the TARDIS . As they dematerialise , Jacko and Sean look on in bemusement . In the TARDIS Jamie admits that , without having a clue what ' s going on , he is enjoying himself . The crew mock the Doctor for not being able to control the TARDIS . He says that this isn ' t true and to prove it he will take them to Mars . He flicks a switch and the TARDIS begins to careen out of control . Home video and audio releases . DVD releases . Contents : Digital releases . After a DVD release of 26 October 2015 , the same version was released