Parts: 4
Writer: David Fisher
Airdates: 25 November 1978 - 16 December 1978
Production Code: 5D

Doctor: fourth
Companion: the first Romana, K-9 mark two

Megalomaniac of the Week: Count Grendel

Story: Romana locates the fourth segment on the forested planet of Tara, where the peasants are skilled in the construction and repair of androids while the nobility live a medieval high life. The Doctor decides that it is the perfect planet on which to take a fishing holiday, so Romana, attired in the latest Taran fashions, sets off on her own to locate the fourth segment and show the Doctor how it's done.

In record time, Romana has found the segment as part of a statue. But no sooner has she collected the converted crystal than a Taran beast rages out of the undergrowth to menace her. Romana is saved from its fanged savagery by the sudden appearance of a chivalrous knight who drives off the creature, but not soon enough to prevent her from spraining her ankle. The knight - who turns out to be Count Grendel, local lord and master of Castle Gracht - brushes aside her protests and whisks her back to the castle, to attend to her ankle and register her mysterious stone. Meanwhile, the Doctor falls in with the company of Prince Reynart, who require his services to repair a faulty replica of the prince intended to draw the attention of any would-be assassins before he is crowned king at the upcoming coronation.

Grendel's outward chivalry belies a ruthless heart, and Romana finds herself in the clutches of a man who wishes to callously use her in an attempt to take Prince Reynart's life and claim the throne for himself. The Doctor sees quadruple as Romana, her local double and android versions of each show up - and not all of them are very friendly. With the help of K9 and his own fencing skills, the Doctor must prepare to do battle with Grendel or watch as Tara falls under his tyrannical reign and Romana is sacrificed to his ambition.