Tom Baker (The Doctor), Lalla Ward (Romana), Matthew Cottle (Mr Maxwell Wilberforce Bell), Abigail McKern (Mrs Lucretia Bell), Robbie Stevens (Mr Jelicho Wigg/ Mr Wilfer Wagstaff), Jane Slavin (Miss Arabella Wagstaff/ Mrs Betsy Wagstaff), John Banks (Silex/ Mr Stoker). Other parts played by members of the cast.
The TARDIS is going underground. When the Doctor and Romana find themselves buried beneath the surface of an alien world, they’re soon swallowed up by a giant burrowing machine. This is where the inhabitants of this planet live – in huge, constantly moving, Drill-towns, chewing up the fuel and resources of the planet in order to survive.
But something else lurks in the earth. Something that feeds on the Drill-towns. Something that is relentless and will not stop.
The Silex are hunting.
Written By: Jonathan Morris
Directed By: Nicholas Briggs
Subterranea was the sixth story in the sixth series of Fourth Doctor Adventures.
The Silex have not been seen in decades.
There have been several wars on Cathon. The Silex were developed during the last one, forcing the inhabitants to go underground.
Although not specifically stated, the idea of the Silex, advanced cyborg-creatures modifying other people to become more Silex in order to be immortal, is reminiscent of the Cybermen, and could possibly be an example of parallel evolution. Similarly, the group-consciousness Silex making Lucretia into their Queen is similar to the Borg from Star Trek: The Next Generation.
Romana says “Oh, look. Rocks.” (Destiny of the Daleks)
Romana is still using her sonic screwdriver. (The Horns of Nimon)