Starman

The first manned expedition to Mars is invaded by an unknown life form, which stows away on the rescue ship.

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.

An alien from Venus tries to take over the world with the help of a disillusioned human scientist, as his wife, his best friend and the friend's wife try to intervene.

A spaceship is sent to Mars after an alien distress signal is picked up. They find one survivor, but when a crew member is found drained of blood it's evident they have rescued a bloodsucking monster. Uses footage from Encounter in Space (1963).

A woman discovers the infidelity of her late husband.