Doctor Who (1963–1989)
6 user 4 critic

The Sea of Death 

On the planet Marinus, the Doctor and his companions are enlisted by Arbitan to seek out the keys to an ancient and powerful machine. Their quest takes them across time and space; will they... See full summary »


John Gorrie


Terry Nation

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Episode cast overview:
William Hartnell ... Dr. Who
William Russell ... Ian Chesterton
Jacqueline Hill ... Barbara Wright
Carole Ann Ford ... Susan Foreman
George Coulouris ... Arbitan
Martin Cort Martin Cort ... Voord
Peter Stenson Peter Stenson ... Voord
Gordon Wales Gordon Wales ... Voord


On the planet Marinus, the Doctor and his companions are enlisted by Arbitan to seek out the keys to an ancient and powerful machine. Their quest takes them across time and space; will they be able to return the keys before Marinus falls under the control of the alien Voord? (Originally broadcast in six parts.) Written by Sarah Hadley

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Release Date:

11 April 1964 (UK) See more »

Company Credits

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Technical Specs

Sound Mix:


Aspect Ratio:

1.33 : 1
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Did You Know?


The Voord that falls down the shaft is a cardboard cutout. See more »


(Around 10 mins) the shadow of a boom mic is visible on the wall behind Ian and Barbara for about 15 seconds. See more »


Barbara Wright: So the men from the glass submarines are intruders like us?
Dr. Who: Yes, but with one difference, which is puzzling but releaving. They died, but we're only prisoners.
See more »


Featured in Dennis Spooner: Wanna Write a Television Series? (2009) See more »

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User Reviews

The Keys of Marinus: Part 1 - Various locations and adventures varying in quality

Review for all 6 episodes:

This story from Dalek creator Terry Nation begins with the episode the Sea of Death. It is in my view an excellent opening episode. It features an intriguing, well written plot with the TARDIS crew searching a strange planet. The design of the planet and its Voord creatures is very good indeed, ideas such as seas of acid and beaches of glass are cleverly used to create a truly interesting and exciting alien planet. The Voord look good, there is menace and suspense, an excellent alien landscape and building design, a proficient script and quality acting all round which gives a 10/10 opening episode to the story.

However, episodes 2-4 are a little disappointing in comparison. The idea of the story means each episode of the first 5 takes place in a different location with a self contained adventure searching for the hidden Keys of Marinus. This really would be a great idea for a story but is a pity when the original world in the opening episode is so well designed. Episode 2 has a hugely different location and features the crew suffering mind control. This second episode is very good in most aspects but a few less impressive aspects such as a minor plot hole cause its quality to suffer. This plot hole is that Barbara is meant to travel, via a kind of teleportation device, just a minute before the rest of the travellers and yet in that minute before they join her numerous things are meant to have happened.

Episodes 3 and 4 are not as interesting or well executed as the first part either with episode 4 the weakest. Episodes 5 and 6 return to a higher standard and are like a murder mystery. Very good but they still are not a match for the top quality first part.

My Ratings: Episode 1 - 10/10, Episode 2 - 8/10, Episode 3 - 7.5/10, Episode 4 - 7/10, Episode 5 - 9/10, Episode 6 - 9/10

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