The earliest British televised production in existence of the play Othello, with black American actor, Gordon Heath, in the title role. This was the first televised version of the play to feature a black actor in the title role. Gordon Heath, an American, came to Britain in 1947 and was cast by Kenneth Tynan to play Othello in his 1950 Arts Council production. The play takes place in Venice and Cyprus and the original production was part-live, with recorded Venice sequences

England, 1891. Ascending writer Oscar Wilde (1854-1900) meets Lord Alfred Douglas, a young nobleman. Over the years, they will maintain an intimate relationship that will be openly criticized by Alfred's father, the Marquis of Queensberry, in such a harsh way that Wilde, instigated by Alfred, decides to sue Queensberry in 1895, accusing him of defamation.

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.

The Doctor, Ian, Barbara and Susan arrive in the TARDIS on board a spaceship. Their initial concern is for the ship's human crew, who are suffering from telepathic interference from the Sensorites, but Susan communicates with the Sensorites and finds the aliens fear an attack by the humans and are just defending themselves. Travelling to the Sense Sphere (the Sensorites' planet) the Doctor seeks to cure an illness to which the Sensorites and Ian have succumbed, but finds it has been caused by deliberate poisoning. The political manoeuvring of the Sensorite City Administrator poses another threat to the TARDIS crew as he seeks to discredit and implicate them.