Planet of the Ood ( TV story ) Planet of the Ood was the third episode of the fourth series of BBC Wales " Doctor Who " . As the title flatly presaged , it featured the return of the Ood and the Doctor ' s first visit to their homeworld . It was the first time viewers met Ood Sigma and the first time they encountered the later - important phrase , " the DoctorDonna " . It also made little to no mention of the " Missing Planets " arc — Donna mentioned the disappearing bees when the Doctor was looking to find what year they were in . This episode included the first sign that the Tenth Doctor ' s life was nearing its end , which would become more evident later on . However the Tenth Doctor ' s death did not happen until a significant amount of time later , making the sign of his end extremely early . Behind the scenes , it was notable for showcasing the first prolonged usage of counter tenor Mark Chambers on a " Doctor Who " score . Later more famous for the purely incidental " Vale Decem " , heard as the Tenth Doctor regenerated , here he gave voice to the diegetic Ood song , known on the series 4 soundtrack as " Songs of Freedom and Captivity " . Synopsis . The Tenth Doctor takes Donna Noble to her very first alien planet : the Ood Sphere . There , the Doctor encounters the Ood once more , and red - eye strikes again . But what is causing it this time ? He and Donna soon learn the horrible secrets kept by Ood Operations , and they discover just what mankind is capable of . Elsewhere , what is the secret Warehouse 15 holds within its walls ? The Doctor arrives , and everything will change . The revolution begins . Plot . A businessman , Mr Bartle , watches an advertisement for the Ood , who are being sold as servants to human s . Bartle is sarcastic yet somewhat impressed with the advert , until he notices that his bosses have cut the price to just 50 credit s each . The man on the other end of the communicator , Klineman Halpen , tells him it is a measure to stay ahead of the competition , and orders him to get going trying to catch up . Bartle orders his Ood , Delta Fifty , to hand him last month ' s military export figures , and tells his assistant Solana Mercurio over the radio to get their buyers to buy them when they arrive . His Ood gives him the domestic files instead of the files requested , and Bartle tells him to get it right . However , rather than obeying , the Ood ' s eyes glow red and he tells Bartle the files are irrelevant . When Bartle asks why , the Ood pressed his translation sphere against Bartle ' s forehead , electrocuting him . As Bartle screams out in pain , the Ood says , " Have a nice day . " Elsewhere , the Tenth Doctor sets the TARDIS to random settings , effectively taking a mystery tour with Donna . After they land , Donna is excited , yet terrified , about landing on an alien planet . The Doctor comforts her by saying that after all his travelling , he still experiences the very same feeling . However , as Donna steps out of the TARDIS , she discovers they have landed on a cold , snowy planet . The Doctor is overjoyed at the sight of finally experiencing real snow . Donna makes several comments about being cold as he continues on about how much he likes the snow . He then waxes poetic to Donna about her first time visiting different planet . As he finishes , he sees that Donna has disappeared . But , Donna exits the Tardis , wearing a heavy winter coat . They then proceed to stroll along the snowy plains of the planet . Meanwhile , Mr Halpen arrives at Ood Operations to cover for Mr Bartle . He is more arrogant than his predecessor . At his office , Halpen , scientist Dr Ryder , and Solana watch a surveillance videotape of Mr Bartle ' s murder . Dr Ryder cannot explain how the translation orb was used to kill Bartle . After Bartle was killed , Delta Fifty escaped . The Ood was shot in the process , and left to die . While Dr Ryder also says that he has no idea about the source of Red Eye , Halpen asks his own Ood , Sigma , for a drink . He explains that it is just hair tonic ; he started losing his hair due to stress built up over the last five years . While the Doctor and Donna roam the planet , the Doctor hears an eerie sound Donna can ' t detect . They find Delta Fifty dying in the snow . Donna seems disgusted by its look . The Doctor tells her the Ood is a " he " , not an " it " . While the Doctor examines him , Donna keeps the Ood talking , to keep him conscious . The Doctor asks why Delta Fifty has been shot . The Ood merely says " the circle must be broken " , before suddenly getting up to attack . Before he can fully stand , he dies . Donna wonders if they should bury him , but the Doctor says to let the snow do the job . As they walk off , the Doctor tells Donna that the Ood are servants to humanity ; they normally aren ' t violent . However , the last time the were possessed by something maleveolent . When Donna asks what , the Doctor tries to avoid the question ; however , she demands an answer . " It was the devil . " the Doctor quips . Donna tells him that if he ' s going to joke , she put her hood up to block him out . However , the Doctor continues on that there must be another source causing the Ood to be psychotic ; they see a rocket fly overhead . Calling it a sports care compared to the TARDIS , Donna races to see where it lands . The Doctor joins her , spotting Ood Operations HQ . Solana Mercurio meets up with the buyers outside the warehouse and tells them to come inside . Just then , the Doctor and Donna arrive . By using the psychic paper , they are able to convince her that they represent the Noble Corporation PLC Limited , Intergalactic ( a fictitious company ) ; in a bizarre twist , Donna gives the entire cover story , while the Doctor makes the psychic paper show what Donna just said . They are greeted as Dr and Mrs Noble , but they quickly correct her that they are not married . Just then , they hear an alarm , which Solana claims is a siren signalling the end of a work shift . In truth , the head of security , Commander Kess , has reported an Ood on the loose . His team pursue the Ood , and eventually corner him . When he turns to the guards , they realise that it is more than a mere case of Red - Eye : this Ood has turned rabid . Halpen orders Kess to send the Ood to Dr Ryder . Solana gives out the presentation on the Ood . She shows three different Ood , one with the standard voice , one with a sexy female voice , and one with a " comedy classic " option ( when being told that the has Ood dropped something , he answers , " D ' oh ! " ) . Afterwards , while the buyers are enjoying the buffet , the Doctor and Donna discover that they are at the Ood Sphere in the year 4126 , during the Second Great and Bountiful Human Empire that spans three galaxies . Donna is fascinated that Earth is still populated , despite all the news articles in her time stating the near end of the world , including global warming and the disappearance of bees . Donna then learns that the red dots on the maps are Ood distribution centres . She decides to talk to an Ood to see if they get a say in this . However , the Ood merely tells them that the Ood were born to serve , or they would die out . The Ood then starts mentioning the circle . The pair decide decide to peruse the base of operations . Halpen , Kess and Dr Ryder take a look at the chained and rabid Ood . The trio are baffled that after two centuries there is a change in them . Ood Sigma is questioned to see if he has seen anything like it , but even he is just as clueless . Dr Ryder suggests they go to Warehouse 15 to find answers . Halpen reluctantly agrees , even though there hasn ' t been any activity there for 200 years . When asked about what to do with the rabid Ood , Halpen orders security to kill it . Meanwhile , the Doctor and Donna observe the Ood being shepherded around . Donna realises the Ood are slaves , not servants . The Doctor tells her it ' s not too different from her time , to which Donna says is not true as she doesn ' t enslave people . The Doctor quips it ' s the people who make her clothes . Angered , Donna asks the Doctor if he takes humans with him on his travels just to take cheap shots at humanity . Apologising , the Doctor remembers that he couldn ' t save the Ood the last time he met them , and never thought to investigate why a species would apparently voluntarily give up their freedom . Now that he knows the truth , and figuring he owes them one ; the Doctor resolves to liberate the Ood . They then observe Halpen . Knowing he ' s the boss , they decide to stay out of his way . Halpen , Dr Ryder and Sigma enter Warehouse 15 , which houses a large , pulsating brain - " the Ood Brain " . Halpen reminisces about his first time to Warehouse 15 when he was six years old , and is still horrified by those memories . Ryder checks the computers and finds no changes in the brain . Halpen is then interrupted by Solana , who informs him that two of the buyers claimed to be members of the Noble Corporation - but the company does not exist . Further , they are now missing . Halpen orders security to search for them , but discreetly . The Doctor and Donna enter a warehouse , finding countless cargo containers . Breaking into one , they see that it contains numerous Ood just standing . Donna wonders why the Ood won ' t just go free . They reply that they don ' t understand the concept . When the Doctor mentions the circle , all the Ood , in unison , say that the circle must be broken , so they can sing . Just then , they are spotted by Commander Kess , who raises the alarm , against Halpen ' s wishes . While Solana lies to the buyers and tells them it is just a fire drill , the Doctor and Donna run . Donna is captured and taken to a container filled with Ood , who have turned to red - eye . Meanwhile , the Doctor is being chased by Kess , who is joyfully trying killing him with a claw . Though the Doctor tries his best to evade it , he eventually falls . He is saved by Solana , who shuts down the claw ' s power and reminds Kess that Halpen wants the two alive . Security eventually lets Donna , who is about to be killed by the red - eye Ood , free . However , the guards forget to re - lock the container , and the red - eye Ood escape from the container too and promptly kill the guard next to the door . Kess and his men open fire as the surrounding containers open as well , giving the Doctor , Donna and Solana time to escape as bullets ricochet everywhere . After making it out , Solana confirms everyone on Earth either knows of the treatment of the Ood or doesn ' t ask . The Doctor asks her to help them . Reluctantly , she points them to the direction where they make the Ood turn to slaves . However , she defects again and calls out for the guards to apprehend the two . The Doctor and Donna head off to the area she pointed out . Kess manages to contain the rabid Ood , but believes the entire batch is contaminated . Seeing no alternative , Halpen orders Kess to get gas canisters . By the time the Doctor finds the area , he hears the Ood song getting stronger , though Donna still can ' t hear it . After they break into the room , they find several Ood in a cage . The Doctor tries to introduce them as " Doctor . . . Donna " . Donna asks the Doctor to let her hear the song . After he is able to open her mind to it , she quickly wants to stop hearing it . It is a very sad song of captivity . He closes her mind to it again ; however , she realises that the Doctor can still hear it , which saddens her more . While Halpen and the team attempt to break into the room , the Doctor enters the cage and discovers that these are " natural " Ood , and carry a hindbrain in their hands . The corporation lobotomises them by removing the brains and replacing them with translation spheres . Donna notes that she spent a long time looking for the Doctor , hoping the universe would be a wonderful place , but didn ' t realise how many issues and horrors await also . " I want to go home , " she says . Moments later , Halpen and the team break in and arrest the two . After they are handcuffed to some pipes , Halpen interrogates them , and gets them to " confess " that they are activists from Friends of the Ood . Halpen claims that the Ood welcomed being turned into slaves , and would be nothing without humanity . Donna snaps at Halpen , calling him an idiot ; the Ood are peaceful , and only wanted to befriend humanity . Instead , Halpen ' s family exploited and mutilated the poor creatures . Impressed with Donna being able to make such a righteous speech , the Doctor congratulates her . The Doctor also learns that Halpen is going to gas the " livestock " , which he likens to how humans dealt with foot - and - mouth disease centuries ago . Meanwhile , the natural Ood appear to have influence over the rest of their kind . They turn every Ood , apart from Sigma , to Red - Eye . In the room with the buyers , Solana notices the Ood turn into red - eye , and urges the buyers to leave . When a drunk and ignorant buyer is killed after foolishly approaching the Ood , the rest quickly oblige , though several are electrocuted in the process . Solana escapes , but doesn ' t make it far - as an Ood appears and kills her . As the gas canisters count down , Kess is captured by the Ood . They subsequently release the captured Ood , and imprison Kess without a gas mask . When the timer reaches zero , Kess dies from the released gas . Outside , Halpen and Ryder witness a full - scale revolution in progress , which the humans are losing , due to them being outnumbered by the Ood . The corporation plans to evacuate and then destroy the building ; Halpen decides to leave the Doctor and Donna behind to be killed by the Ood as executing them with gunshots to the head would leave too many questions when an investigation is conducted . The Doctor confronts him about a supposed third element , and wants to know what it is . Halpen replies , " It won ' t exist for very much longer " , before leaving . Halpen and Dr Ryder make it down to Warehouse 15 , while witnessing the Ood revolution in full swing . As the Doctor and Donna attempt to break free without any success , three red - eyed Ood enter the room and plan to kill them . The two of them repeatedly tell them , " Doctor , Donna , friends " and " The circle must be broken " . Through the mild telepathic link with their adapted brethren , the natural Ood are able to hear them . They pass the knowledge of who is a friend to the Ood on to the three , returning them to docile mindsets . The Ood free the Doctor and Donna , who are trying to find the source of the third element . On the way , they see Sigma , who was generously allowed to leave by Halpen to join his people ; Sigma guides them to Warehouse 15 . Once inside , the Doctor finds the giant Ood brain . It is the Ood ' s telepathic centre and the third part of the Ood physiology . Six pylons surround the brain , which has been used to dampen the telepathy between brain and Ood for 200 years , forcing them to be servants . They are interrupted by Halpen , who holds them at gun point . Ryder tells them that he has surrounded the area with land mine s to kill the brain ; since it is the third link in the Ood way of life , this will kill every Ood in the universe . The Doctor theorises that the brain spent 200 years adapting to the pylons , but Dr Ryder claims responsibility . He exposes himself as a member of FOTO - the Friends of the Ood ; knowing that the natural adapting process would take too long , he spent ten years infiltrating Ood Operations and working his way up the corporate ladder . Once he finally had access to the warehouse ( a few hours previously ) , he lowered the barrier to its minimum setting , allowing the oppressed Brain to wreak vengeance on those that imprisoned it . In response , Halpen pushes him over the edge , and he is engulfed by the brain . As Halpen is about to shoot the Doctor and Donna , Sigma steps in and insists he take another drink . Halpen , disturbed by Sigma ' s insistence , asks the Ood if he has poisoned him , but Sigma denies such , declaring that natural Ood do not kill . He reveals that Halpen ' s " hair tonic " is in fact Ood graft suspended in a biological compound . The Doctor realises that the Ood subconsious is divided into three groups : red - eye is revenge , rabid is anger , and the seemingly unaffected Sigma represents its patience . The Ood have been preparing for Halpen for a long time , and with him in such close proximity to the brain , he begins to hear to Ood ' s telepathic song . With the Ood graft he has consumed rewriting his biology , he bends down and peels away his human skin from his head , revealing the cranium of an Ood . The slimy , skin - coloured tentacles of an Ood come out his mouth , while Donna looks on in horror . When Halpen stands up , he has been fully transformed before their eyes , then sneezes out his new hind brain , and showing it to the amazed Doctor and Donna . Sigma states " He has become Ood - kind , and we will take care of him " . Donna notes that after being with the Doctor , she doesn ' t know what is right or wrong anymore , to which the Doctor replies , " It ' s better that way . People who know for certain tend to be like Mr Halpen " . After the Doctor shuts down the mines , he asks Sigma if he can shut down the pylons damping the telepathic field . Sigma readily agrees , and with the push of a lever the pylons are switched off , and the circle is broken . The Ood can sing again . The Ood song erupts to a new , joyful one , and now everyone can hear it , even Donna . Outside , the fighting stops - the Ood group themselves together , whilst the soldiers stand down . Afterwards , the Doctor and Donna are outside the TARDIS , and explain to Sigma that the song resonated to the three galaxies . The humans , realising that the Ood can think and feel like them and demonstrating the immense kindness they are capable of , decide to free the Ood and send them back home . After Sigma thanks them , he offers them a place in their song , but the Doctor says he has his own song . Sigma tells him his song will end soon , since every song must end . The Doctor turns to Donna to see what she wants ; after the freeing of the Ood , she has changed her mind and wants to continue her travels with him . Before they leave , Sigma tells them they will never be forgotten ; their children and children ' s children will sing of the DoctorDonna . Their names will be carried by the Ood Sphere ' s wind , ice and snow forever . The TARDIS vanishes as the Ood watch .