Inside the TARDIS

While searching through a cupboard Romana discovers a Mark III Emergency Transceiver which, when placed into the TARDIS console, picks up a distress call. To investigate this distress call the TARDIS takes The Doctor, Romana and K9 to the planet Chloris.

On leaving the TARDIS they discover that Chloris is a lush and verdant world but has a chronic shortage of all metals so making it rare and prized commodity. This has resulted in a band of scruffy thieves, led by Torvin, organising raids on the palace of the planet’s ruler, the icy and callous Lady Adrasta, to steal whatever metal they can get their hands on. Lady Adrasta however, controls the planet’s very last metal mine and keeps order, with the aid of her Huntsman and his wolfweeds - mobile balls of vegetation -, so that she can retain full control over the planet’s limited supply of metal.

The Doctor identifies the distress signal’s source as a large eggshell-like structure in the forest at the Place of Death, but before he can investigate further he is captured and taken by Lady Adrasta’s guards. He is taken to her throne room where he discovers it contains an array of metal items including a shield patterned in the same way as the remnants of the shell. He soon finds himself sentenced to be thrown into a deep Pit - a fate that befalls all who oppose Lady Adrasta.

The Doctor and K9

Meanwhile Romana finds herself captured by a party of scavengers, ever keen to find and hoard more metal, and they are particularly impressed by the possibilities of K9 who comes to Romana’s rescue when he is summoned from the TARDIS. K9 though enables Romana to escape and they are both briefly reunited with The Doctor.

Romana is shocked, however, when The Doctor, in order to escape from Lady Adrasta and her guards, jumps into the Pit. As he falls into the darkness he manages to cling to its sides so allowing him to make his way safely to the bottom.

Lady Adrasta

At the bottom he discovers that he is at the entrance to a cave system. While searching the tunnels The Doctor he meets Organon and elderly soothsayer. Organon was formally Lady Adrasta’s astrologer, who fell foul of Lady Adrasta when his predictions did not come true – and so found himself also thrown into the pit.

The Doctor also discovers that the Pit is the home to a very large green globular creature which oozes through the passages and suffocates those who are fed to it. The Doctor, with the aid of the Organon discovers that the creature is not an unthinking killer, but an ambassador from the planet Tythonus.

Tythonus has a lack of chlorophyll but has abundance of metal and so the Tythonians had hoped to trade with Chloris but unfortunately the first person their ambassador Erato encountered on arriving, in his eggshell-like ship, was Lady Adrasta who took his communicator device and trapped him in the Pit. She did this when she realised that if more metal was brought to her planet then her monopoly on it would be broken.

Organon

On discovering the truth The Doctor lures Lady Adrasta into the tunnels. But Lady Adrasta is trapped and killed by Erato. The bandits, who were robbing Lady Adrasta’s palace while she was otherwise occupied, come across Erato’s communicator. However, as soon as they touch the communicator it exerts an influence over them and they are compelled to carry it to the Tythonian.

Reunited with his communication device Erato warns The Doctor that his own people have already retaliated for his imprisonment by setting a neutron star on a collision course for Chloris. And it is due to collide within the next twenty-four hours.

Working against the odds, to prevent Chloris from being destroyed, The Doctor arranges for Erato to be freed from the Pit and using the TARDIS, they travel into space to intercept the approaching neutron star. Then Erato, using his reconstituted spacecraft, spins an aluminium shell around the star, allowing it to be pulled off course by the TARDIS’s gravitational tractor beam. Thus neutralise the danger and so saving Chloris.

Back on Chloris, The Doctor’s last act before leaving is to arrange for a mutually beneficial trade agreement to be put in place between Chloris and the Tythonians.