(IAN is escorted into the room by TARRON. (IAN whirls around to see that a dark-haired youngish man, wearing a similar black uniform to the man who was on the floor, is seated on the far side of the room in front of a series of display cabinets containing regalia and other ornaments.) CORRIDOR OUTSIDE THE APARTMENT
(They hear someone coming and are forced away.) EYESEN: Members of the tribunal, the evidence already offered is more than enough to ensure the conviction of this man but add to it, the fact that under psychometric examination, this mace was found to have been held in the right-hand of the prisoner. He must have told his plans to someone else. It was brought to the city years ago by a man called Arbitan. You know the purpose of the micro-key?
Plan: A: The TARDIS; Q: What ship arrives on the planet Marinus? A: the planet Marinus; Q: Where does the TARDIS arrive on an island of glass surrounded by a sea of acid? A: The travellers; Q: Who is forced by the elderly Arbitan to retrieve four of the five operating keys to a machine called the Conscience of Marinus? A: the keeper; Q: What is Arbitan's role in the Conscience of Marinus? A: their own sinister purposes; Q: What do the evil Yartek and his Voord warriors plan to use the Conscience of Marinus for? Summary: The TARDIS arrives on the planet Marinus on an island of glass surrounded by a sea of acid. The travellers are forced by the elderly Arbitan to retrieve four of the five operating keys to a machine called the Conscience of Marinus, of which he is the keeper. These have been hidden in different locations around the planet to prevent them falling into the hands of the evil Yartek and his Voord warriors, who plan to seize the machine and use its originally benevolent mind-influencing power for their own sinister purposes.