The Hand of Fear ( TV story ) The Hand of Fear was the second story of season 14 of " Doctor Who " . Significantly , it was Elisabeth Sladen ' s final story as a member of the regular cast of " Doctor Who " . " The Hand of Fear " was originally intended for the 1976 six - part slot that was taken by " The Seeds of Doom " . It was inspired by the 1946 film . ( DCOM : " The Hand of Fear " ) There were several versions of the script . One saw the hand as an advance guard preparing the way for an alien army . Another fixed upon two " Omegans " — representing the " hawk " and " dove " — working against humanity . There were plans for the Brigadier and Harry Sullivan to appear , with the former , much like in early drafts of " Pyramids of Mars " , bowing out from " Who " in a blaze of glory . However , script editor Robert Holmes took issue with its complexity and commissioned another script to be the final story of season 13 , should this remain unresolved . Finally , in October 1975 , " The Hand of Fear " was officially delayed and " The Seeds of Doom " was produced in its place . After Elizabeth Sladen told the production team she wanted to leave early in the next season , Douglas Camfield was commissioned to write " The Lost Legion " , which would see Sarah killed at its conclusion . However , Holmes was unhappy with the script and , in a turn of fate , decided that " The Hand of Fear " might have to be used as a replacement . With UNIT and degenerating - humans removed from the plot , Bob Baker and Dave Martin produced a more linear story . Camfield fell behind on his own script and was discounted . Baker and Martin left the writing of Sarah ' s farewell scene to Holmes . Director Lennie Mayne made his final contribution to " Doctor Who " with " The Hand of Fear " . After finishing production on the serial and an episode of , he was drowned after a wave swept him overboard in the English Channel . Permission to film at Oldbury Nuclear Power Station was obtained before the script was completed , so central was it to the story . Bob Baker found the staff very accommodating on his initial visit , such was their enthusiasm for the project . The radiation provided health and safety concerns , with geiger counter checks being performed on the cast and crew and Radiological Clearance Certificates having to be issued before any object could leave the premises . ( DCOM / INFO : " The Hand of Fear " ) Synopsis . When the TARDIS lands in a quarry on Earth , the Doctor and Sarah are caught in a mining explosion . Sarah is found clutching what appears to be a fossilised hand , buried in one - hundred - fifty - million - year - old strata . Analysis shows the hand to be silicon - based and inert , but when Sarah begins to act as if possessed , the Doctor suspects that it may still be alive . . . Plot . Part 1 . One hundred and fifty million years ago on the planet Kastria , a traitor named Eldrad is sentenced to death for crimes including the destruction of the barriers that kept the solar wind s at bay . Placed into a capsule and shot into space , Eldrad awaits obliteration . The capsule is detonated prematurely , despite the risk of particle survival . Conditions are deteriorating rapidly on Kastria . The remaining Kastrian s await their fate on the desolate planet . The Fourth Doctor and Sarah Jane Smith arrive in the TARDIS in a modern - day quarry on Earth and are caught immediately in a quarrying explosion . The Doctor is slightly injured . Sarah is found unconscious in the rubble , clutching a fossil ised hand . She is taken to a local hospital . The hand is examined . Based on the strata of the rock in which it was found , it is one hundred fifty million years old . Pathologist Dr Carter dismisses these findings as ridiculous . Examining a sliver of the hand under an electron microscope , the Doctor observes a helix similar to DNA . The minuscule radiation of the microscope causes the sample to grow . The Doctor realises that this fossil might actually contain vestiges of life . Sarah awakens in her hospital bed , holding a crystalline ring that slipped from the hand . The ring begins to pulse with energy . Sarah hears a voice in her head : " Eldrad must live . " She steals the hand and flees the hospital , knocking out Carter with a flash from the ring . She heads for the nearest nuclear reactor , the Nunton Complex . With the aid of the ring , Sarah overpowers guards and workmen and enters the reactor room . She watches as the hand absorbs radiation , regenerates its missing finger and begins to move . Part 2 . The head of the complex , Professor Watson , stays at his post when the reactor goes critical . He offers the Doctor aid and advice in trying to get to Sarah . She sits serenely amidst the chaos and klaxons . The Doctor resolves to enter the chamber through a cooling duct in Cooling systems control . His progress is interrupted by Dr Carter , now also under the hypnotic control of the ring . He tries to strike the Doctor while on a stairwell , but his own momentum carries him over the railing , and he falls to his death . The Doctor enters the chamber and finds there is no radiation whatsoever ; the hand is absorbing the entire output of the reactor . Sarah is removed , and the hand placed in a sealed cabinet . The Doctor breaks through Sarah ' s hypnosis . The ring , however , is left behind in the chamber . It is found by a technician named Driscoll , who falls under its control . He takes the hand and makes his way to the reactor core . He uses the ring against the security personnel who attempt to stop him . The Doctor pursues him , closely followed by Sarah , and narrowly avoids becoming a victim of the ring . They catch up with Driscoll just as he is about to enter the core and set off a chain reaction . The Doctor pulls Sarah to the ground to await the explosion . Inside the control room , the panels explode , knocking Professor Watson to the floor . . . Part 3 . It seems they are waiting in vain , as nothing happens . The Doctor enters the reactor chamber where the level of radiation is , surprisingly , still normal . He explains that sort of " unexplosion " happened . They close the reactor core and hurry out as Watson ordered an RAF strike to destroy the hand and the reactor . The missiles ' impact , however , have no effect because the hand absorbed all the energy . The nuclear missiles and the full power of the reactor are enough to complete the regeneration of Eldrad . Crystalline , silicon - based and female , she tells the story of how she created the spatial barrier s that let Kastria thrive , but in an interstellar war the barriers were destroyed , and she was disgraced and condemned . Eldrad persuades the Doctor to return her to Kastria so she can save her people ; he agrees on the condition that they travel to Kastria in the present , a hundred fifty million years after she left . Immediately afterwards , Watson arrives and attempts to attack Eldrad , firing a gun at her with no effect . She immediately retaliates and means to kill him , but she is persuaded otherwise by the Doctor . Leaving Watson to work on getting Nunton back to normal , the Doctor , Sarah and Eldrad return to the quarry where the TARDIS landed , and depart for Kastria . The planet is barren and ruined , but her ring reactivates some instruments . The Kastrian opens the door to the underground thermal caves looking for survivors and triggers a trap . A syringe - like dart hits her in the chest . Part 4 . After she explains that the dart contained an acid of her own design , the Doctor and Sarah take the dying Eldrad to a regenerator chamber deep below the surface of Kastria , in the thermal chamber s . Booby traps have been set along , targeting silicon - based beings . The regenerator chamber is rigged to destroy Eldrad , but a malfunction allows a full regeneration . The new form of Eldrad emerges and reveals he had based his earlier form on Sarah , the first human he encountered . Eldrad is now much taller and male . He boasts that he destroyed the solar barriers in a rivalry with King Rokon . They find Eldrad ' s ultimate goal , to rule Kastria . He enters the Kastrian race bank , where he intends to revive the dormant Kastrian people . The bank , however , is empty . An image of Rokon appears on a video screen , informing Eldrad that without the barriers , facing perpetual subterranean existence and a small possibility of his return , the Kastrian race elected to destroy themselves and the race bank . It was Rokon who long time ago set the booby trap s . Rokon mockingly salutes Eldrad from the grave as " King of Nothing " . A bitter Eldrad now decides to rule the Earth instead and demands that the Doctor return him . He refuses , stating that his obligation to Eldrad is now satisfied . Eldrad pursues the Doctor and Sarah , but they stretch out the Doctor ' s scarf across the passageway . Tripping over it , Eldrad falls into an abyss to his apparent doom . The Doctor drops Eldrad ' s ring into the depths as well . He notes that Eldrad ' s fate is uncertain , as silicon - based lifeforms are difficult to kill . The Doctor and Sarah depart in the TARDIS , and the Doctor sets about making repairs . Sarah bemoans her life in the TARDIS — bouncing around the universe , fleeing from bug - eyed monsters and needing a bath . The Doctor is focused on his work on the TARDIS console , which infuriates her . She demands to be returned home and storms off to her room to pack . While she is gone , the Doctor receives a telepathic summons to return to Gallifrey and notes to himself that he cannot take Sarah with him . Sarah returns with her packed things , and the Doctor informs her that he must return her to Earth , as he cannot take her with him to Gallifrey . With her idle threat suddenly becoming reality , Sarah is taken aback , especially at missing the chance to see Gallifrey . The Doctor steers the TARDIS to bring her to Hillview Road , South Croydon — Sarah ' s home . She asks him not to forget her ; he replies likewise . Once the TARDIS dematerialises , Sarah makes her exit , noting that travel does indeed broaden the mind , and the Doctor promises her that they will meet again . After watching the TARDIS disappear to return the Doctor home , Sarah realises she hasn ' t been left on Hillview Road and guesses she ' s probably not even in South Croydon . She playfully remarks to a nearby dog , " He blew it " , and , whistling , walks off toward her new life . . . Home video and audio releases . DVD releases . This story was released as " Doctor Who : The Hand of Fear " . Released : Contents : Notes : It was also released as issue 43 of " Doctor Who DVD Files " . VHS releases . This story was released on VHS in February 1996 , and was the final videocassette to include the diamond logo on the cover artwork in the United Kingdom and the US . It was available for only two weeks , being deleted along with much of the rest of the " Doctor Who " video range shortly after . The original videocassette thus became something of a collectors ' item . Digital releases . " The Hand of Fear " is available through both iTunes and , in the UK , Amazon Instant Video . On iTunes , it is included in the " Best of Tom Baker " bundle , alongside " Genesis of the Daleks " , " The Deadly Assassin " and " The Talons of Weng - Chiang " .