The Doctor has returned to the planet Karn. There, Ohila of the Sisterhood, explains that someone has been seeking him across all time and space. She asks the Doctor if he will go, insisting: "You owe that creature nothing." He says that he will, but that he will first 'hang out' for a bit.
Another prologue to the episode, titled "The Doctor's Meditation", was released in Russia, Canada, the United States and Denmark on 15 and 16 September 2015, alongside a 3D cinematic release of "Dark Water" and "Death in Heaven". On 18 September, this was released on Facebook in the United Kingdom, and also made available through other online channels. In this prologue, the Doctor appears in medieval times alongside Bors, who appears to be a loyal friend, and in the 6 minute clip, questions who he must face, asking whether he faces an old friend or a foe. The Doctor replies that he must meditate, but has trouble doing so.
In an unknown time period, a war takes place on an extraterrestrial battleground, fought with a mixture of primitive and advanced technologies. While running across a war zone, a boy becomes trapped inside a field of 'handmines'. The Doctor arrives and tries to save the boy, tossing him his sonic screwdriver so they can communicate and encouraging him to survive. However, when the Doctor asks the boy his name, he is shocked and horrified when the boy says his name is Davros, future creator of the Daleks.
Centuries later, a creature named Colony Sarff, an agent of Davros, visits several worlds in search of the Doctor. His message for the Doctor is that Davros is dying and that "Davros knows, Davros remembers". He reports to an ailing Davros that the Doctor cannot be located. Davros, still in possession of the Doctor's screwdriver, advises Sarff to seek the Doctor's friends, as they will be able to locate him.
On present day Earth, Clara is summoned by UNIT to help them contact the Doctor. Kate Stewart reveals that every plane that is currently airborne has frozen, and no-one knows why. While trying to determine who froze the planes and why, UNIT receives a message on a channel specifically created for the Doctor, should he ever need to contact them. The message's sender turns out to be Missy, who arranges to meet with Clara in an open-air café. Missy confirms that she froze the planes because she also needs Clara's help in finding the Doctor, as she cannot locate him as well. Missy shows Clara the Doctor's confession dial – a Time Lord's equivalent of a "last will and testament", traditionally delivered on the day prior to a Time Lord's death – which had been sent directly to her. Missy takes this to mean that the Doctor believes he has only one more day to live, and she is concerned for him.
Clara and Missy track the Doctor to Essex in the year 1138, where he has spent three weeks partying. The trio's reunion is cut short when Colony Sarff appears, having followed the women to the Doctor's location. He reveals himself to be not a single entity but rather a colony of vipers composed of one large snake and several smaller serpents, filling out a monk-style robe to appear humanoid. He threatens everyone in the arena, but the Doctor rebuffs him. He then relays Davros's message for him and presents the Doctor's screwdriver. Shame overwhelms the Doctor – it is revealed (in flashback) that he didn't save the boy Davros but, instead, had abandoned him – and he agrees to be taken prisoner. Clara and Missy, over the Doctor's objections, insist on coming along as fellow prisoners; and Colony Sarff agrees. In the meantime, Bors, the Doctor's medieval friend – in actuality, a Dalek puppet – procures the Doctor's TARDIS for the Daleks.
Sarff takes the three to what appears to be a space station. The Doctor is brought to Davros, who tells him that he remembers what he did to him. Meanwhile, Missy notices that the gravity doesn't feel artificial, as would be expected on a space station. She opens the air lock and the pair step out into what looks like space, before discovering that they are actually standing on a planet. The planet becomes visible and, much to Missy and Clara's horror, is revealed to be Skaro, the Daleks' homeworld.
Missy and Clara are then captured by Daleks and taken to the TARDIS, which the Daleks intend to destroy, as Davros makes the Doctor watch. Missy offers her services to help them utilize the TARDIS rather than destroy it, but instead is seemingly exterminated. The Doctor begs Davros to save Clara, but Davros claims he cannot control the Daleks. Clara freezes as the Daleks wait for her to run. When she does, she is also apparently exterminated. They then proceed to use a laser to destroy the TARDIS, leaving the Doctor alone and powerless. Davros derides the Doctor's compassion as his "greatest indulgence" and wants him to confess, finally, that "compassion is wrong."
The episode concludes with the Doctor back on the battlefield with young Davros, who asks if the Doctor's come to save him. The Doctor – claiming he's from the future – brandishes a Dalek gun and says he's going to save his friend the only way he can...
A Kaled soldier is depicted armed with a bow and arrow; this is an allusion to a line spoken by Harry Sullivan in Genesis of the Daleks: "they're going to finish off with bows and arrows".
Colony Sarff visits the Maldovarium, a bar last seen in 2011's "A Good Man Goes to War". The scene features several returning aliens: the Sycorax, the Hath, the Ood and a Tivolian. The Shadow Proclamation, an intergalactic police force last appearing in 2008's "The Stolen Earth", also briefly returns, featuring the Shadow Architect (from the same episode) and a Judoon.
The Sisterhood of Karn, already seen in the 2013 teaser "The Night of the Doctor", originally appeared in the 1976 serial The Brain of Morbius.
UNIT seeks the Doctor using a computer algorithm, plotting on a map the locations of various crises at which he has been rumoured to have appeared. These correspond with locales for many of the Doctor's past adventures: San Martino (The Masque of Mandragora); Troy (The Myth Makers); New York City (The Chase, "Daleks in Manhattan"/"Evolution of the Daleks", and "The Angels Take Manhattan") and three possible appearances in Atlantis (The Time Monster, The Underwater Menace, and The Daemons).
Davros plays excerpts from his prior conversations with the Doctor's earlier incarnations, ranging from Genesis of the Daleks to "The Stolen Earth". Most notably, he shows footage (from Genesis of the Daleks) of the Fourth Doctor asking the question "if someone who knew the future pointed out a child to you and told you that that child would grow up totally evil, to be a ruthless dictator who would destroy millions of lives, could you then kill that child?"
Several different designs of the Daleks from across the series' history reappear in the episode, alongside their creator, Davros, and their home planet, Skaro. The first Dalek shown in the episode is a blue-and-silver model as first seen in 1963.
Clara, upon deducing the Doctor's location and intent, says "Do not go gentle into that good night", the first line of the titular poem by Dylan Thomas.
When the Doctor spies Clara and Missy, he plays the opening notes to Roy Orbison's "Oh, Pretty Woman".
The Doctor's playing electric guitar and teaching medieval people the term "dude" echoes the movies Bill & Ted's Excellent Adventure and Bill & Ted's Bogus Journey, films featuring two rocker teens who travel back in time – in a telephone call box – and teach historical figures their customs. Capaldi himself plays the guitar and was part of a punk rock band called The Dreamboys during the 1980s alongside Craig Ferguson.
Shooting on the episode began on 12 February. To provide the necessary Dalek props, some were taken from the nearby Doctor Who Experience exhibition. Scenes set on Skaro's surface were filmed on Tenerife, one of the Canary Islands. Another of the Canary Islands, Lanzarote, has been used as a filming location twice previously, in 2014's "Kill the Moon" and in 1984's Planet of Fire.
Kelly Hunter had previously appeared as the Shadow Architect in the Series 4 episode "The Stolen Earth", with Julian Bleach also having appeared as Davros in that episode and its conclusion, "Journey's End". Clare Higgins played Ohila of the Sisterhood of Karn in the mini-episode "The Night of the Doctor", which was part of the 50th Anniversary specials in 2013, and again in the season finale "Hell Bent". Jami Reid-Quarrell made a subsequent appearance as "The Veil" in "Heaven Sent", the penultimate episode of Series 9.
The trailer for the episode was released on 5 September 2015.
A cinema screening of "The Magician's Apprentice" was held on 27 August 2015 in Edinburgh as part of The Guardian Edinburgh International Television Festival. It was also screened along with "The Witch's Familiar" on 10 September 2015 in Cardiff by BAFTA Cymru with a Q&A session following.
The episode was watched by 6.54 million viewers, the lowest consolidated rating for the programme since the Matt Smith episode "The Crimson Horror". There were 1.3 million "download requests" through the BBC's iplayer service. The overnight viewing figures indicated the episode was watched by 4.58 million viewers on BBC1, the lowest overnight figure for a series opener since the show returned in 2005. It gained a 21.2% share of its timeslot and came second for the night, behind The X Factor. It received an Appreciation Index score of 84. The episode broke records on BBC America with 1.1 million viewers in the 18–49 category. All together, 1.97 million watched on the night in America.
"The Magician's Apprentice" received critical acclaim. The episode received a score of 92% on Rotten Tomatoes based on 13 reviews, with an average score of 8.6. The site's consensus reads "In "The Magician's Apprentice," Peter Capaldi and the writers settle into an emotionally engaging tone while raising the stakes for the Twelfth Doctor".
Jim Shelley of The Daily Mail, described it as "a sharp, fast, thrilling, piece of historic, futuristic, television: the BBC at its best." and that only "feeble theme tune and underwhelming opening credits" let it down. Scott Collura of IGN awarded the episode a 9.4 out of ten, deemed "amazing". He went on to say "The Twelfth Doctor can have lots of fun in this episode, but he can also hit some real dark patches too. And it’s the climatic reveal/cliffhanger here that will help bring this Doctor towards the latter emotional state". He further praised the episode's writing, stating that the episode "[delivers] a real jolt to the system for both the Doctor and the viewer to start off Season 9".
Patrick Mulkern of Radio Times rated the episode as 5/5, praising the episode's story and concept. He said "Steven Moffat promised us a season opener that feels like a finale and, boy, does he deliver. In fact he delivers boy. Boy Davros. A brilliant idea – just waiting for someone to have it". But tempers it with "there’s no real sense of jeopardy"....In a universe where everything is now "unzappable'". Nick Setchfield of SFX also gave the episode five stars, claiming it was "full of wit and menace" and "unafraid to take on the show's museum piece classics". However, Benji Wilson in The Daily Telegraph gave it 3/5 saying that the "jury is still out" and questioning whether "seemingly catastrophic events" can be very thrilling in the Doctor Who universe which "keeps reminding you you're not supposed to take it seriously".