The Impossible Planet ( TV story ) The Impossible Planet was the eighth episode of the second series of BBC Wales " Doctor Who " . It marked the first appearance of the Ood . The episode was also rife with allusions to the realm of Hell and its ruler , the Devil . This episode shows one of the rare moments that companions shares the same opinions of the Doctor . Upon learning that the TARDIS didn ' t translate a language , both stated that they should leave before breaking out into laughter ; they would never pass up a chance to explore the unknown . The prequel to " The Impossible Planet " , " Tardisode 8 " , allows viewers to witness the presence of Captain Walker , who would later die during his crew ' s expedition and only receive posthumous mention in this episode . Synopsis . The Tenth Doctor and Rose Tyler lose the TARDIS down a deep chasm , leaving themselves stranded on a space base positioned on a planet in the orbit of a black hole . Meanwhile , an entity who identifies as Satan himself is awakening and beginning to cause chaos amongst the crew . Plot . The TARDIS materialises inside a " Sanctuary Base " meant for deep - space expeditions . The Tenth Doctor and Rose discover the words " Welcome to Hell " written above lines of unknown characters scribbled on the station wall . The Doctor says that it must be incredibly old , as the TARDIS is unable to translate it . After a slight misunderstanding when first meeting the Ood , a docile race of empathic servants who work on the station , the travellers meet the crew of the base , led by acting Captain Zachary Cross Flane . An earthquake occurs and they all have to take cover . The crew is introduced to Science Officer Ida Scott , Head of Security John Jefferson , trainee maintenance officer Scooti Manista , and archaeologist Toby Zed . They are on an expedition on an anomalous planet in orbit around a black hole , K37 Gem 5 . The Doctor realises that it is impossible for the planet , which is called Krop Tor , to be in around the black hole , as it should be pulled in like the star systems around it are . He calculates that it would take a phenomenal amount of power ( a power source with an inverted self - extrapolating reflex force of six to the power of six every six seconds ) to generate the huge gravity field stabilising its orbit . The field extends out as a distinct gravity funnel into clear space , which allowed the expedition a way in to the planet . The funnel is not a natural phenomenon , and the crew is drilling ten miles underground to the core of the planet in hopes of finding the power source and using it . The origin of the power source is an ancient civilisation that had been on Krop Tor , and the inscription on the wall is a transcription of fragments found on the planet during their drilling . The Doctor soon discovers that storage sections 5 to 8 had collapsed as a result of the earthquake - like tremor they had experienced moments after their arrival , dropping the TARDIS , which had been in Storage 6 , into a crevice . With no resources to divert the drilling , Rose and the Doctor are stranded . Ida offers to put them on the duty roster . The crew goes back to their duties . Toby begins to hear a voice addressing him , but the person tells Toby not to look at him , otherwise he will die . An Ood tells Rose that the Beast awakens to make war against God . A horned image is displayed out of the corner of Zach ' s eye and the computer system tells Danny , " He is awake . " The voice speaks to Toby , and the symbols from the pottery he was holding appear on his skin . He passes out . Ida opens the window so they can watch as the remains of the Scarlet system are swallowed by the black hole . Rose can ' t call her mum , as there is no signal on her superphone for the first time . She and the Doctor talk about the future until Rose ' s phone rings to tell her , " He is awake . " They go to ask Danny about the Ood . Danny attempts to reassure them , showing a telepathic field monitor , which goes up to Basic 30 , a reading six times normal . The Ood respond to , " He is awake " with " and you will worship him . " Toby wakes with red eyes and symbols all over his face . Meanwhile , Scooti goes to Toby ' s room to drop off paperwork , but finds his room empty . While she puts the paperwork on the desk , the computer announces the opening and closing of Door 41 , an airlock . Concerned , she rushes to the airlock , where the computer confirms that the door opened and closed . The computer cannot tell who went outside and says no spacesuit was taken . Through a window she sees Toby in the winds on the barren planet ' s surface , without a spacesuit , although there is no breathable air . Toby turns around to look at her and with a gesture cracks the glass between them , Scooti tries to run towards Door 40 , but it will not open . The glass shatters and alarms blare as air begins rushing out of the base . Scooti is dragged away , screaming as she loses her grip . The base begins to shake violently and Zach orders them to evacuate the affected section . Danny , Rose , the Doctor , Jefferson , Ida , and two security guards all rush to the nearest safe corridor . Jefferson pulls a clear skinned , pale eyed Toby through last , then closes the door , sealing the breach . Zach then asks if everyone was all right . Jefferson then reports that everyone is accounted for except Scooti . Jefferson then calls for Scooti on his radio . However , he gets no answer . Zach then tells them she is alright and that her biochip located her in Habitation 3 . Jefferson and Ida sigh in relief . They then go down to search for Scooti while the Doctor and Rose tend to Toby . When Toby , Rose , and the Doctor enter the habitation they find the searchers looking frantically . Ida is calling all the habitations looking for Scooti . Jefferson then reports that Scooti is still missing while Zach continues by saying that her biochip says she is in Habitation 3 . Then the Doctor sadly says he found her . Scooti is floating outside in the vacuum . Jefferson reports her death to Zach . Ida then goes over to the control to close the overhead , saying Scooti was only twenty years old . Scooti floats away towards the black hole , spinning as the door closes . Jefferson recites a verse from " Horatius , " a poem by Thomas Babbington Macaulay : " And how can man die better / Than facing fearful odds / For the ashes of his fathers , / And the temples of his gods . " Ida realises that the drill has stopped , meaning they ' ve managed to drill down to the core of the planet . Nonessential Ood are to be confined . The Doctor talks Zach into letting him volunteer for the mission to investigate . He and Ida journey down the mine shaft and into a massive cavern with ancient giant sculptures along its walls . They head for the power source , guided by sensor readings , and find a large circular disk set in the floor of the cavern , which the Doctor suspects is a trap door of some sort . Meanwhile in the base , Danny calls from where he is monitoring the Ood to report that the Ood ' s telepathic field has risen dangerously to Basic 100 . Basic 100 is high enough to induce brain death , but they are obviously still alive . Ida reports the edge of the massive door is covered in the ancient symbols and they ask Toby if he ' s translated any . Toby says he knows what it says , and he looks up at Jefferson and Rose through red eyes in a symbol covered face . He says they are the words of the Beast . He continues to speak , then taunts Jefferson before the symbols flow from his face to the Ood . Toby faints , and the different groups of red eyed Ood begin to speak and advance . They identify themselves as the Legion of the Beast and recite his verses as they begin to advance on the crew members . The security guard with Danny is electrocuted by a translator ball . Danny runs . In the other chamber , Jefferson , Rose , and their guard retreat . The Doctor and Ida stand before the sealed metal door on the cavern ground . Rocks fall as the ground shakes , even to the base above , and the sections of the door fall apart and slide open to show a black chasm . Zach reports they ' re losing orbit , as the Ood back Rose ' s group into a door that won ' t open . The Doctor and Ida run back to the edge of the chasm as a voice calls out , " The pit is open , and I am free ! " As the Doctor and Ida look down , malevolent laughter echoes . . . International broadcast . When aired by the Canadian Broadcasting Corporation in late 2006 , this episode was considered a mid - season cliffhanger , with " The Satan Pit " and the rest of the season not airing until early 2007 , after a hiatus of several months . At the time the CBC made this decision a trend had developed among North American networks to insert lengthy ( sometimes months - long ) breaks during the November - January period .