The Creature from the Pit ( TV story ) The Creature from the Pit was the third story in season seventeen of " Doctor Who " . This was the last story directed by Christopher Barry , who had first worked on the show since 1963 . It was the first story produced , though not the first broadcast , to feature Lalla Ward as the Doctor ' s companion . This story was one of season seventeen ' s many " downsized " stories . This meant that the Doctor would be working on a smaller scale rather than saving the universe as he had been throughout the past season . The serial made use of complicated model work to achieve the space scenes ; the original scene had to be filmed again . The Erato prop was also a major problem . A puppet version was unavailable for rehearsals and there wasn ' t time for a redesign . Synopsis . The Doctor and Romana receive a distress signal and arrive on Chloris . It is a lush and verdant world with only small quantities of metals , all of which are controlled by its ruler , Lady Adrasta . Adrasta keeps order with the aid of her Huntsman and his Wolfweed s - mobile balls of vegetation . A band of thieves , led by Torvin , organise raids on her palace to steal whatever metal they can . But in the mines of Chloris is something huge , a creature thrown into the pit to be forgotten . . . and the Doctor is about to join him . Plot . Part one . An MK3 Emergency transceiver on the TARDIS identifies a distress signal and brings the craft to the lush jungle world of Chloris , where metal in all forms is a rare and prized commodity . The Doctor , Romana and K9 venture out to discover the remains of an enormous egg in the jungle . The Doctor is immediately beset by Wolfweed s under the control of the Huntsman . He releases the Doctor and orders his death . Karela countermands him and has the Doctor and Romana taken prisoner . As they travel through the jungle , bandits attack them . Romana is taken prisoner . The Doctor is taken to the palace of the Lady Adrasta , who rules the planet by controlling all the metal . The Doctor examines the throne room and takes particular interest in a plate upon the wall . Romana uses a dog whistle to summon K9 . With his help , she escapes the bandits . The Doctor is taken to a pit to witness the execution of one of Adrasta ' s men , an engineer who failed to make some of the observations The Doctor made . He is thrown to a creature that lives within the vast caverns below . Romana arrives and tries to help the Doctor escape as K9 attacks the guards . However , the Wolfweeds quickly surround and disable K9 . The Doctor then jumps into the pit . Part two . Romana notices that the Doctor is still alive , clinging to the side of the pit . He signals to keep silent as to his survival . Adrasta decides that Romana may be of use , as will the metal K9 . The Doctor loses his grip and falls into the pit . Meanwhile , Lady Adrasta tries to get information out of Romana . Her guards slowly hammer away at K9 . Eventually Romana tells her that only K9 knows what Adrasta wants . In the woods , the bandits decide to attack the palace , believing that the guards will be searching for them . Within the Pit , the Doctor encounters Organon , an astrologer thrown there by Adrasta . They escape from the creature ' s tentacle and then burn it to deter it from attacking again . They begin exploring the caverns . K9 tells Adrasta about the TARDIS . With such a machine , Adrasta no longer needs the creature . She decides that K9 will kill it for her . They venture through a passage into the caverns of the pit . The Doctor , Organon and a number of Adrasta ' s guards come across the creature . The guards attack it , to no effect , and the creature squashes the Doctor . Part three . The guards and Organon retreat . The creature forms a barrier to prevent their return . Within the cavern , the Doctor awakes , seemingly unharmed . Outside the palace , the bandits make their attack and quickly gain access to the throne room . In the pit , Adrasta decides that K9 will destroy the barrier . The Doctor tries to befriend the creature but it has no way to communicate with him . The creature draws a picture of the plate that the Doctor noticed in Adrasta ' s throne room . At that moment , the bandits are stealing the plate . They are interrupted by the guards and retreat into the cavern . The plate activates and Torvin and Edu fall under its hypnotic effect . K9 is unable to break down the barrier . It gets stronger with each blow . From the other side , the Doctor bursts through . Adrasta questions how the Doctor did this . He replies that he " asked very nicely " . Adrasta admits she knows more about the creature than she admitted . It is a Tythonian . The Doctor uses a mirror to reflect K9 ' s attacks , killing Adrasta ' s guards and scaring off Karela . The Doctor holds Adrasta despite her pleas . She orders Romana to have K9 kill the creature . The hypnotised Torvin and Edu approach , still carrying the plate , which they place on the creature . Part four . With the plate , the creature is able to speak through the person touching it . The Doctor uses the plate . The creature ' s name is Erato . It is the Tythonian ambassador to Chloris . It came fifteen years earlier to negotiate a treaty exchanging metal for chlorophyll . Its craft was the vast egg in the jungle . However , Adrasta , knowing her power depended on control of the planet ' s metal supply , imprisoned Erato . Knowing the truth , her people turn on her . The creature exacts its revenge by crushing Adrasta to death . In the woods , Karela meets the bandits and kills Torvin . She tries to convince the bandits to join her in taking the metal . The Doctor arrives and has K9 destroy the metal the bandits stole . With nothing to lose , the bandits and Karela give up . The Doctor has rescued the Tythonian just in time . Tythonus has declared war on Chloris over the missing ambassador and has dispatched a neutron star to collide with Chloris ' star and destroy the system . It will collide within the next twenty - four hours . Working desperately , the Doctor uses the TARDIS to stabilise the star while Erato weaves an aluminium shell around it . The danger is neutralised . The Doctor ' s last act on Chloris is to push Organon , now one of the de facto rulers , toward a mutually beneficial trade agreement with Erato and the Tythonians . Story notes . Production errors . " to be added " Home video and audio releases . DVD releases . It was released as issue 149 of " Doctor Who DVD Files " .