The Rani has taken control of the planet Lakertya and forced the peaceful Lakertyans to build a rocket silo-cum laboratory base into a cliff face. She is aided by the Tetraps, a race of bat-like creatures, and plans to fire a rocket loaded with loyhargil, a substance with the same properties as strange matter, at an asteroid completely composed of the latter.
As a preliminary to this she has created a huge artificial brain and kidnapped a number of geniuses – Including Pasteur and Einstein from Earth - to imbue it with the ability first to identify and then to calculate the correct way to create loyhargil for her in the laboratory. The newly-regenerated Doctor and Mel must stop her and save the planet…
Special Features Include : Commentaries, Behind the Scenes, Makings of, Photo Gallery, Storyboards and Subtitles