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.)
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
So the men from the glass submarines are intruders like us?
Yes, but with one difference, which is puzzling but releaving. They died, but we're only prisoners.