Doctor Who and the Invisible Enemy, by Terrance Dicks, Target 1979.
Number 36 in the Doctor Who Library. 110 pages, paperback. Original script by Bob Baker and Dave Martin, BBC 1977.
This adventure features the 4th Doctor and Leela, and introduces K-9.
SUMMARY
A relief ship en route to Titan passes through and is attacked by a mysterious cloud. Upon arrival on Titan, the ship crew kills everyone except Lowe, who escapes but manages to send a May Day. One of the ship crew locks Lowe in a room and turns off the oxygen and tries to cancel the May Day. It’s revealed that the ship crew is infected with a virus.
The TARDIS receives the May Day and passes through the same cloud and is attacked. The Doctor is affected but Leela is not. They continue to Titan. In the adventure, Leela rescues Lowe while the Doctor struggles for control of his mind by the virus that’s infected him. At some point, Lowe is infected but no one else is aware. The Doctor, Leela, and Lowe take the TARDIS to an asteroid that houses the medical complex where the Doctor puts himself in a coma and where they meet Professor Marius and his mechanical dog companion, K-9. Meanwhile on Titan, the remaining crew prepares an empty fuel tank for spawning of the virus.
Lowe begins infecting the medical complex personnel while the Doctor has Marius make clones of he and Leela. The Doctor’s clone fetches the Relative Dimensional Stabilizer from the TARDIS and uses it to miniaturize the clones, which have a limited lifespan. They are injected into the Doctor’s bloodstream while he is in coma again to find and kill the virus. Lowe gets past Leela and K-9 and infects Marius. Marius clones and miniaturizes Lowe and injects him into the Doctor’s bloodstream. The clones of the Doctor and Leela find the Nucleus in the Doctor’s brain but they are too late and dissolve into the Doctor’s bloodstream, as does the clone of Lowe.
Marius pulls a tear from the Doctor’s tear duct and reverses the RDS to maximize what they’re expecting to be the Doctor and Leela or Lowe but turns out to be the Nucleus. It plans to spawn at this size now and is taken by ship back to Titan for spawning. It plans to feed the Doctor to its swarm but Leela rescues the Doctor and returns them the TARDIS with K-9. The TARDIS can’t go anywhere because the RDS is still in the infirmary. K-9 creates diversion and the Doctor and Leela go back to the infirmary where the Doctor creates a cure for the virus and retrieves the RDS. Marius is cured and his crew begins making batches of anti-virus.
The Doctor, Leela, and K-9 return by TARDIS to Titan where the Doctor tries to use the anti-virus but it is destroyed. He locks Lowe in the chamber with the Nucleus and wires it to blow up. The chamber explodes, destroying the Virus of the Swarm. The Doctor and Leela return to the asteroid long enough to say good-bye to Marius but leave with K-9 with Marius’ blessing.
OPINION
It’s a standard novelization of an episode that skirts between the gothic Philip Hinchcliffe tone and the lighter Graham Williams tone. I enjoyed it better in print, if for no other reason, I didn’t have to actually look at the Nucleus costume. The book paces well and the story introduces viewers to K-9.
SOURCES
http://www.shannonsullivan.com/drwho/serials/4t.html
http://www.drwhoguide.com/who_4t.htm