'The Horns of Nimon' (4 Parts) Story Code '5L' by Anthony Read

The TARDIS is immobilised for repairs, but it falls into a gravity whirlpool. The Doctor and Romana encounter a damaged spaceship from the planet Aneth, which is taking a consignment of young men and women to the planet Skonnos, where they are to be presented as a tribute to the Nimon, a bull-like creature that lives at the centre of a labyrinthine complex. The Nimon has promised the Skonnon leader, Soldeed, that he will return Skonnos to its former glory if he is supplied with young humans and hymetusite, a radioactive crystalline substance, which the warlike Skonnos have pillaged from the peaceful planet of Aneth. The Doctor repairs the Skonnon spaceship, but is left behind by the treacherous co-pilot, who kidnaps Romana and takes her and his cargo to Skonnos. Arriving on Skonnos, the sacrifices, Romana and the co-pilot are sent by Soldeed into the Nimon's complex. After the Doctor manages to repair the TARDIS, he follows his companion to Skonnos, and discovers that the Nimon is using the crystals to build a black hole, which will be used to bring the other members of his race to Skonnos. The Nimon jump from planet to planet, draining them of their energy and resources like a plague of galactic locusts; one of their number is always sent ahead to take advantage of the unsuspecting inhabitants, in order to pave the way for the invasion. Romana inadvertently travels in a Nimon capsule to the other end of the black hole, to a dying world called Crinoth. Here she meets Sezom, the last survivor of the planet, who gives her a staff that can be used to destroy the Nimon. She returns to Skonnos, where she, the Doctor and the sacrifices enlist K-9's aid to escape the complex. The Doctor destroys the Nimon complex, marooning the creatures on Crinoth, where they will perish, and the Anethans return home.

Tom Baker (Doctor Who), Lalla Ward (Romana), David Brierly (Voice of K9), Graham Crowden (Soldeed), Michael Osborne (Sorak), Malcom Terris (Co-Pilot), Bob Hornery (Pilot), Janet Ellis (Teka), Simon Gipps-Kent (Seth), Robin Sherringham, Bob Appleby, Trevor St John Hacker (Nimons); Clifford Norgate (Voice of the Nimons), John Bailey (Sezom)

Produced by Graham Williams
Directed by Kenny McBain

TX:
Part 1 - 22nd December, 1979 @ 6.10pm - 6.35pm
Part 2 - 29th December, 1979 @ 5.50pm - 6.15pm
Part 3 - 5th January, 1980 @ 6.20pm - 6.45pm
Part 4 - 12th January, 1980 @ 6.05pm - 6.35pm

Notes:
*Featuring the Fourth Doctor, the Second Romana, and K-9 MKII