Roots: The Quatermass Experiment (alien genetic material brought back from a space mission), The Thing (an alien that can take over humans by infecting them with its genetic material), Night of the Living Dead, The Evil Dead, and other Zombie movies. Lovecraft is mentioned.
Dialogue Triumphs: The Doctor on his role in the universe: 'You may not like me. You may not like what I do, what I shall have to do. But I'm here to help you, and it may be that I'm the only help you have.'
Continuity: The Doctor tells Peri that when running in a new supply of Zeiton-Seven, it is necessary to recalibrate everything, hence his frustration at forgetting to check the date when he and Peri leave. He drinks Fisherman's Ruin, the local beer. He likes children, and demonstrates various card tricks to the local schoolchildren. When Peri suggests that Vampires might be behind the events on the Dorsill Islands, he crosses his fingers whilst dismissing the idea! He is familiar with the European Space Agency's Gatherer probes, despite their top-secret status [probably due to his UNIT connections]. He is immune to the genetic infection of the Denarian. He has learned how to fly a helicopter (see Fury from the Deep).
Peri gets infected by the Denarian, but is cured by the Doctors antidote.
Gatherer Three was the third space probe launched by the European Space Agency, and was designed to bring back rock and ice samples in sealed containers from the outer reaches of the Solar System; instead, it brought back genetic material, capable of repairing tissue damage, no matter how severe, which Christopher Sheldon dubbed Denarian (from DNA). It doesn't know when to stop repairing its host however, and tries to improve it. In its first generation, it infected Sheldon, and used him as an incubator for its genetic material; hence his colleagues removed constantly regenerated fingers and limbs from him in order to grow more of the Denarian. Once a secondary host was infected, the Denarian entered its second generation, which involves keeping the host alive via its tissue repair abilities and infecting further hosts, so that it has somewhere to live; because it has no effect on the human brain in its first or second generation state, it cannot recognise when its host is dead, and so reanimates its host's brain-dead corpse. It also directs the secondary hosts to harvest tissue from Sheldon. The third generation Denarian realises that it needs to control the host in order to proliferate and begins to take control of human minds, producing a group consciousness. The Doctor notes that Denarian itself is not conscious, but is merely proceeding through its life cycle, which Sheldon and his colleagues unwittingly enabled it to do. The Denarian is susceptible to X-Rays, although a dose strong enough to kill it will also kill the human host. The Doctor manages to destroy the infection with an antidote made from a hybrid strain of the Denarian.
The Dorsill islands are located off the South-West Coast of Britain and have remained in a largely pre-industrialised state, by the choice of the locals. Concessions are allowed, such as modern medicine and a satellite telephone for emergencies. Christopher Sheldon bought the islands from the islanders six months earlier, when their trust fund for running the island went bust and they were under threat of development.
Links: The Doctor has just installed the Zeiton-Seven that he obtained on Varos (Vengeance on Varos), but still needs to recalibrate the TARDIS (see More Short Trips: Moon Graffiti).
Location: Dorsill and Sheldon's Folly, c. 1990s.
The Bottom Line: A pleasant little story that keeps the reader enthralled without getting bogged down in continuity. As usual with Richard's novels, there are animated corpses and plot twists, and the characterisation of both the regulars and supporting characters is spot on. And it's nice to see the Doctor save the day single-handed, a rare occasion in the novels.