The Mark of The Rani is the third serial of the 22nd season in the British science fiction television series Doctor Who, which was first broadcast in two weekly parts from 2 February to 9 February 1985. This story is the first to feature the renegade female Time Lord known as the Rani.
Something is amiss in the mining village of Killingworth, in 19th-century England. Miners are being gassed in the washhouse and transformed into thugs and vandals, attacking men and machinery, being perceived as Luddites by other locals. The Sixth Doctor and Peri Brown witness the phenomenon when they arrive in Killingworth looking for the cause of some sort of time distortion, and he also notices one of the rampaging miners has a strange red mark on his neck. With his usual audacity, The Doctor foists himself upon the local landowner, Lord Ravensworth, who is concerned by the ferocity of the local Luddite attacks, with the most passive of men suddenly turning violent and unpredictable.
The answer lies in the local washhouse. The Master has turned up at this key point in human history and forces his way into the presence of the old woman who runs the washhouse: in reality another Time Lord known as the Rani. She is a gifted chemist and is using the set-up of the washhouse to anaesthetise the miners and distill from them the neurochemicals that enable sleep. This is what accounts for the red mark on the victims. These chemicals are then synthesised for use back on Miasimia Goria, a planet she rules and which the Master visited, where her other experiments have left the inhabitants without the ability to rest. He persuades her that they need to deal with the Doctor together, but also steals some of the precious brain fluid she collected to ensure her collaboration. It is a rocky partnership, full of half-truths and deceptions. The Master heads off to deal with the Doctor, egging on local miners to attack his enemy and persuading some of them to throw the Doctor's TARDIS down a mineshaft.
The Doctor has meanwhile dressed as a miner and infiltrated the bathhouse, where he soon deduces the Rani's schemes. She entraps him but he still challenges her ethics, prompting her to reveal she has been coming to Earth for centuries to harvest her precious chemicals. The Doctor, strapped to a trolley, is placed on top of a mine cart by a group of rowdy miners and pushed down a slope. The cart rattles along its rails, fast approaching the gaping entrance to the mineshaft...
Luckily, the inventor George Stephenson saves the Doctor just in time. Later, the Doctor and Peri visit Stephenson in his cottage. Stephenson has planned a meeting of scientific and engineering geniuses in the village. The Doctor is worried about the wisdom of such a meeting in the current circumstances, but elsewhere the Master is so desperate to see the event take place he uses mind-control over Stephenson's young aide, Luke Ward, telling him to kill anyone who tries to prevent it. The Master wants to use the finest brains of the Industrial Revolution to help speed up Earth's development and then use the planet as a powerbase. He strikes a deal with the Rani that she may return to Earth at any time to harvest more brain fluid if she helps him achieve this.
While the villains are away, the Doctor returns to the washhouse and dodges the booby traps to find a way into the Rani's TARDIS. Her control room contains jars of preserved dinosaur embryos. She summons her ship to the old mine workings using a remote control device, with the Doctor still inside. He hides while his adversaries converse, with the Rani confessing to have also laid landmines in nearby Redfern Dell; and when the coast is clear the Doctor slips away to report back to Ravensworth, Stephenson and Luke, whom he sees is behaving strangely.
To make herself useful Peri is using her botanical knowledge to make a sleeping draught for the afflicted miners, but her quest for herbs leads her to Redfern Dell. The Doctor gets there in time to save her, but not before Luke accidentally steps on a mine and is turned into a tree. The Doctor then surprises the Master and the Rani, who are lurking at the edge of the Dell, and takes them prisoner with the Master's own Tissue Compression Eliminator. Peri is given charge of them but the Rani's deviousness outstrips the Master's and she is the one who enables them to escape. The Rani and the Master flee in her TARDIS, but the Doctor has also developed a trick or two: he has sabotaged the navigational system and velocity regulator, and the ship starts heading out of control. In the destabilised condition, one of the jars containing an embryo Tyrannosaurus rex falls to the floor and the creature begins to grow, affected by the time spillage. The Master and the Rani are "stuck" against one of the walls of the Rani's TARDIS, due to the speed at which they are travelling; and are helplessly at the mercy of the rapidly aging immature Tyrannosaurus.
The Doctor and Peri make an exchange with Ravensworth, who has retrieved the TARDIS and accepts the phial of brain fluid, which he is told to administer to the affected miners. Before the eyes of an astonished scientist and his financier, the TARDIS departs…
Kate O'Mara reprised the role of the Rani twice, in the Seventh Doctor's debut story Time and the Rani (1987) and the 30th anniversary charity special, Dimensions in Time (1993). The Master returns in this story, with no explanation given as to his escape from what appeared to be a fiery demise at the end of Planet of Fire (1984).
The working titles for this story were Too Clever By Far and Enter The Rani. This would be the last Doctor Who story to have a female director until the 2007 Tenth Doctor episode "Blink" (directed by Hettie MacDonald).
The music score for this story was provided by composer Jonathan Gibbs. John Lewis was originally hired to compose the score, but a sudden onset of illness — which ultimately resulted in his death — prevented him being able to finish the work and forced the production team to give the assignment to Gibbs just after Lewis had completed scoring the first episode. Lewis' score for the first episode was included on the DVD release.
The serial featured extensive location filming at the Blists Hill Victorian Town and the Coalport China Museum, operated by the Ironbridge Gorge Museum Trust. Both episodes included in the credits: "The BBC wish to acknowledge the cooperation of the Ironbridge Gorge Museum." This was the first story since Season 3's The Gunfighters to feature specific historical characters, in this case landowner Lord Ravensworth and his employee George Stephenson.
Writing for Radio Times, Mark Braxton described the serial as "a refreshing, earthbound delight in an undistinguished era of offworld futurama". He praised the location filming, the scenes between the Doctor, the Master and the Rani, and aspects of the design, such as the Rani's TARDIS, which he said was "absolutely gorgeous, quite the best piece of design in the show for an age". However, he characterized the dialogue as "a mixture of wonderful and woeful", questioned the low-key presence of the historical characters, the "shaky" period grasp and wandering North East accents, and concluded the serial was "a story of considerable interest. But little flair or sizzle".
Paul Cornell, Martin Day and Keith Topping considered the story's dialogue to be overblown although the concepts were interesting. They were impressed by the direction and music for the scene where the Doctor's inspected the inside of the Rani's TARDIS, and concluded the serial was "Altogether rather more impressive than its reputation."
A novelisation of this serial, written by Pip and Jane Baker, was published by Target Books in January 1986.
The Mark of the Rani was released on VHS in July 1995. It was released as a Region 2 DVD on 4 September 2006.  As of 11 August 2008, this serial has been released for sale on iTunes. This serial was also released as part of the Doctor Who DVD Files in issue 63 on 1 June 2011.