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 assistant Emma, he is actually in communication with them, so they hear his plans. The Doctor invites his old foe to meet him on the planet Tersurus. The planet is in ruins, and was the home of a now-vanished 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, because he too has a TARDIS and persuaded the architect of the building to put in a secret death trap. The Doctor had anticipated this and traveled 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.