Synopsis
A parody of the original series, Curse begins with the Master gloating over his latest scheme to destroy his arch-nemesis. However, instead of only spying on the Doctor and his companion Emma, he is actually in communication with them, so they hear his plans. The Doctor invites his old foe to meet him at an old castle on the planet Tersurus. The planet is in ruins, and was the home of a now-extinct race of supremely-enlightened beings shunned by all because they used flatulence as their means of communication. They all died when one of them discovered fire.
The Master appears, gloating that he travelled a century back in time, and persuaded the architect of the castle to put in a secret death trap. The Doctor had anticipated this and travelled further back, persuading the same architect to sabotage the trap. The Master had also anticipated this, and arranged for an additional trap - with identical results because the Doctor had likewise anticipated his move. The Doctor informs the Master, having calculated that he "has saved every planet in the known universe a minimum of 27 times", and having grown tired of battles with aliens and "the endless gravel quarries", that he is retiring, having found a Companion - Emma - with whom he has fallen in love. The Master springs yet another trap; a trap door under the Doctor's feet leading to the vast sewers of Tersurus, which he intends to suggest to the architect after going back in time again and buying him an expensive dinner. However, the Doctor had already bought the architect that dinner, so when the Master pulls the lever the trap door opens beneath him instead.
Seconds later, as the Doctor and Emma start to leave, the Master bursts in. Having taken him three centuries to crawl out, he emerges as an old man covered in sewage. Using his TARDIS to return to the present, he has brought allies - the Daleks (who, lacking noses, are the only race that will have anything to do with him). Additionally, he has been enhanced by superior Dalek technology, a Dalek SuctionCup Hand. To the Master's dismay he can not answer when Emma asks him what the suction cup is for. The Master throws himself at the Doctor but falls into the sewers again, and immediately bursts in again, another three hundred years older. The Daleks give chase to the Doctor, knocking the Master once more into the sewers. Having spent a total of 936 years in the sewers with only snails for food, companionship, and romance, he returns using a zimmer frame and is easily outpaced by the slow moving Daleks.
Emma and the Doctor, trying to escape, are captured when they run into a room full of Daleks. Rather than being exterminated immediately, they are tied to chairs aboard the Dalek ship. (Why the legless Daleks would have chairs, as well as leave the Doctor and Emma alive, is something they "will explain later".) The Master, now young again, exclaims that he has been enhanced with Dalek technology again - rejuvenating him and adding "Dalek bumps" attached to his chest. To make things worse the Doctor makes several comments, alluding to the "Dalek bumps" as breasts. In return for his enhancement, the Master intends to give the Daleks a weapon of vast power - the Zektronic energy beam - a weapon that would "allow the Daleks to conquer the universe in a matter of minutes"... by means that will be explained later.
When the Doctor tells the Daleks they'll have to share the universe "with the beard and the bosoms over there", they inform the Doctor that they plan to exterminate the Master after he has assisted them. The Doctor uses the Tersuran language (farting) to warn his fellow Time Lord, undetected by the Daleks, who don't have noses. The Master helps the Doctor and Emma to escape, but not before the Doctor is fatally injured. He tells Emma (in Tersuran, which the Master translates) that he loves her, then dies. The Master notes that "this is only his ninth body", upon which the Doctor regenerates into a handsome and sexually eager new Doctor (Richard E. Grant). Forced to fix the Dalek weapon, so that it won't explode and implode, he is electrocuted and becomes a shy, middle-aged and overweight Doctor (Jim Broadbent). Another accident results in a handsome, smooth-mannered Doctor (Hugh Grant), but this Doctor is also accidentally killed while fixing the weapon.
Time Lords can regenerate twelve times, but the weapon's energy prevents his twelfth regeneration, so it seems the Doctor is permanently dead. The Master vows to live a life of heroism in honour of his fallen foe's memory, as do the Daleks.
But (perhaps through the will of the universe itself) the Doctor does regenerate yet again, only this time as a woman (Joanna Lumley). Emma is deeply disappointed, pointing out quite literally that "You're just not the man I fell in love with." The Master, however, is quite smitten with this new Doctor, who notices the sonic screwdriver has "three settings!" The story ends with them walking off together.
Read more about this topic: Doctor Who And The Curse Of Fatal Death