Doctor Who season 16

The sixteenth season of British science fiction television series Doctor Who, known collectively as The Key to Time, began on 2 September 1978 with The Ribos Operation and ended with The Armageddon Factor. The arc was originally conceived by producer Graham Williams, who had proposed it as part of his application for the producer's job in 1976.^[1] The name refers to a powerful artefact, the segments of which are what the Fourth Doctor and his companions, Romana and K9, search for during the season. Anthony Read continued in his role as script editor from the previous season. Douglas Adams also became script editor alongside Read.

Doctor Who
Season 16
DVD box set cover art
Starring	Tom Baker Mary Tamm John Leeson
No. of stories	6
No. of episodes	26
Release
Original network	BBC1
Original release	2 September 1978 (1978-09-02) – 24 February 1979 (1979-02-24)
Season chronology
List of episodes

Synopsis

A figure calling himself the White Guardian commissions the Doctor and K9, assisted by a new companion, the Time Lady Romana, to find the six segments of the Key to Time, a cosmic artefact resembling a perfect cube that maintains the equilibrium of the universe. Since it is too powerful for any single being to possess, it has been split into six different segments and scattered across space and time, disguised by the raw elemental power within them into any shape or size. However, since the forces balancing the universe are so upset, the White Guardian needs to recover the segments of the Key to stop the universe so that he can restore the balance. The White Guardian also warns the Doctor of the Black Guardian, who also wishes to obtain the Key to Time for his own purposes. In the final episode, the Black Guardian, disguised as the White Guardian, attempts to take the Key from the Doctor. However, the Doctor sees through the figure's charade and orders the segments of the Key to Time to once again become scattered across all of time and space, bar the sixth, which he reinstates as Princess Astra. Afterward, the Doctor decides to install a device called a randomiser into the TARDIS' navigation system for a period of time to make his following voyages unpredictable to evade the Black Guardian.

The six segments

In some stories, the segment in its disguised form is an integral part of the story, whereas in others, the segment is merely an incidental object.

1. The first segment is disguised as a lump of Jethrik, a valuable rock mineral on the planet Ribos.
2. The second is the planet Calufrax, shrunk to miniature size by the space-hopping pirate planet of Zanak.
3. The third is the Great Seal of Diplos, a jewelled pendant which had been stolen by a criminal of that planet and brought to Earth.
4. The fourth is part of a statue on the planet Tara.
5. The fifth was an unspecified religious artifact that had been consumed by a squid on the swamp world of Delta Magna's third moon, causing it to turn into a gigantic monster named Kroll that the natives worship as a god.
6. The final segment is a woman, the Princess Astra of the planet Atrios.

Casting

See also: List of Doctor Who cast members

Main cast

• Tom Baker as the Fourth Doctor
• Mary Tamm as Romana
• John Leeson as Voice of K9

Tom Baker continued his role as The Fourth Doctor, and saw the introduction of Romana played by Mary Tamm. This season was the only one to feature Tamm as the first incarnation of Romana, as Tamm left the programme after only one season because she felt that the character had reverted to the traditional assistant role and could not be developed further.^[2] The second incarnation, played by Lalla Ward (who also appeared in this season as Princess Astra), began her run in the first serial of the next season (Destiny of the Daleks).

Serials

See also: List of Doctor Who episodes (1963–1989)

Douglas Adams took over as script editor from Anthony Read for The Armageddon Factor. Season 16 consists of one long story arc encompassing six separate, linked stories.

No. story	No. in season	Serial title	Episode titles	Directed by	Written by	Original release date	Prod. code	UK viewers (millions) [3]	AI [3]
98	1	The Ribos Operation	"Part One"	George Spenton-Foster	Robert Holmes	2 September 1978 (1978-09-02)	5A	8.3	59
			"Part Two"			9 September 1978 (1978-09-09)		8.1	—
			"Part Three"			16 September 1978 (1978-09-16)		7.9	—
			"Part Four"			23 September 1978 (1978-09-23)		8.2	67
The Doctor is recruited by the White Guardian to seek the six segments of the Key to Time. The quest for the first segment takes them to Ribos, a medieval planet that galactic confidence trickster Garron is trying to sell to the Graff Vynda-K.
99	2	The Pirate Planet	"Part One"	Pennant Roberts	Douglas Adams	30 September 1978 (1978-09-30)	5B	9.1	61
			"Part Two"			7 October 1978 (1978-10-07)		7.4	—
			"Part Three"			14 October 1978 (1978-10-14)		8.2	64
			"Part Four"			21 October 1978 (1978-10-21)		8.4	64
The quest for the second segment takes them to the planet Zanak, which has been hollowed out and fitted with hyperspace engines, allowing its insane cyborg Captain to materialise it around other smaller planets and plunder their resources.
100	3	The Stones of Blood	"Part One"	Darrol Blake	David Fisher	28 October 1978 (1978-10-28)	5C	8.6	—
			"Part Two"			4 November 1978 (1978-11-04)		6.6	—
			"Part Three"			11 November 1978 (1978-11-11)		9.3	—
			"Part Four"			18 November 1978 (1978-11-18)		7.6	67
The quest for the third segment takes them to Earth, where an ancient criminal who stole the segment disguises herself as the Celtic goddess Cailleach.
101	4	The Androids of Tara	"Part One"	Michael Hayes	David Fisher	25 November 1978 (1978-11-25)	5D	9.5	—
			"Part Two"			2 December 1978 (1978-12-02)		10.1	65
			"Part Three"			9 December 1978 (1978-12-09)		8.9	—
			"Part Four"			16 December 1978 (1978-12-16)		9.0	66
The quest for the fourth segment takes them to the planet Tara. The Fourth Doctor and Romana find themselves embroiled in the political games of the planet Tara, where doppelgangers, android or otherwise, complicate the coronation of Prince Reynart.
102	5	The Power of Kroll	"Part One"	Norman Stewart	Robert Holmes	23 December 1978 (1978-12-23)	5E	6.5	—
			"Part Two"			30 December 1978 (1978-12-30)		12.4	—
			"Part Three"			6 January 1979 (1979-01-06)		8.9	—
			"Part Four"			13 January 1979 (1979-01-13)		9.9	63
The quest for the fifth segment takes them to the third moon of Delta Magna, caught in the middle of a dispute between the crew of a methane refinery and the natives (known as 'Swampies').
103	6	The Armageddon Factor	"Part One"	Michael Hayes	Bob Baker and Dave Martin	20 January 1979 (1979-01-20)	5F	7.5	65
			"Part Two"			27 January 1979 (1979-01-27)		8.8	—
			"Part Three"			3 February 1979 (1979-02-03)		7.8	—
			"Part Four"			10 February 1979 (1979-02-10)		8.6	—
			"Part Five"			17 February 1979 (1979-02-17)		8.6	—
			"Part Six"			24 February 1979 (1979-02-24)		9.6	66
The quest for the sixth and final segment takes them to Atrios, a world at war with its planetary neighbour Zeos. But the Black Guardian is closing in.

Broadcast

The Key to Time was broadcast from 2 September 1978 to 24 February 1979.

Home media

See also: List of Doctor Who home video releases and List of other Doctor Who home video releases

VHS releases

Season	Story no.	Serial name	Number and duration of episodes	UK release date	Australia release date	USA/Canada release date
16	98	The Ribos Operation	4 x 25 min	April 1995	June 1995	September 1996
	99	The Pirate Planet	4 x 25 min	April 1995	June 1995	September 1996
	100	The Stones of Blood	4 x 25 min	May 1995	July 1995	March 1996
	101	The Androids of Tara	4 x 25 min	May 1995	July 1995	March 1996
	102	The Power of Kroll	4 x 25 min	June 1995	August 1995	September 1996
	103	The Armageddon Factor	6 x 25 min	June 1995	August 1995	September 1996

DVD and Blu-ray releases

All releases are for DVD

Season	Story no.	Serial name	Number and duration of episodes	R2 release date	R4 release date	R1 release date
16	98–103	The Key to Time[a]	26 × 25 min.	—	—	1 October 2002[4]
		The Key to Time: The Ribos Operation The Pirate Planet The Stones of Blood The Androids of Tara The Power of Kroll The Armageddon Factor	26 × 25 min.[b]	24 September 2007[c] 16 November 2009[d][5]	7 November 2007[6]	3 March 2009[7]

1. Stories available in Region 1 only, with minimal restoration and extras (individually or as a box set)
2. Special edition. Known collectively as The Key to Time. Only available as a box set in Regions 2 and 4. Stories available individually or as a box set in Region 1. All serials contain four episodes each, apart from The Armageddon Factor, which has six episodes.
3. Limited release
4. Re-release

In print

See also: List of Doctor Who novelisations

Season	Story no.	Library no.[a]	Novelisation title	Author	Hardcover release date[b]	Paperback release date[c]	Audiobook release date[d]
16	098	52	Doctor Who and the Ribos Operation	Ian Marter	13 December 1979		3 March 2011
	099	—	The Pirate Planet (unabridged)	James Goss	5 January 2017	1 February 2018 [e]	5 January 2017
			Doctor Who and the Pirate Planet (abridged)		—	11 March 2021	—
	100	59	Doctor Who and the Stones of Blood	Terrance Dicks	20 March 1980
		—	The Stones of Blood	David Fisher	—	14 July 2022[8]	5 May 2011
	101	3	Doctor Who and the Androids of Tara	Terrance Dicks	24 April 1980		—
		—	The Androids of Tara	David Fisher	—	14 July 2022[9]	5 July 2012
	102	49	Doctor Who and the Power of Kroll	Terrance Dicks	29 May 1980		7 October 2021
	103	5	Doctor Who and the Armageddon Factor		26 June 1980		6 June 2019

1. Number in Target's Doctor Who Library, if applicable
2. Published by Target's parent companies (Allen Wingate, W. H. Allen, BBC Books) unless otherwise indicated
3. Published by Target Books (or by BBC Books under the Target Collection umbrella) unless otherwise indicated
4. Unabridged from BBC Audio/AudioGo unless otherwise indicated
5. Published by BBC Books