The TARDIS materialises on the Artifact in the 26th century. The Artifact is immense hollow orb, populated by a variety of unpleasant alien-forms. The Artifact has only recently arrived in the Elysium system, which is contested by three different factions. It’s presence has only served to increase tensions as its gravitational distortions provide an opportunity to reach Earth.
On the surface of the Artifact the time travellers are separated. In addition to being menaced by the increasingly hostile life forms they meet two other visitors to the planet, Midnight and Mark Bannen, both of who have been mutated by the Artifact and gained a degree of symbiosis.
They learn that the Artifact is actually a space-faring lifeform and will soon lay eggs the size of planets. The resulting offspring will likely devastate the entire galaxy. The stakes are raised as the Doctor becomes comatose to prevent his mind being absorbed, Ace suffers radiation sickness and Bernice becomes infected with parasites.
With the Artifact about to give birth the time travellers must find their way back together to save themselves and the rest of the Elysium system.
There are distinct shades of ‘Lucifer Rising’ to this story. Both concern immense alien artifacts whose function is slowly discovered through the course of the story. Mark Bannen is even revealed to be the son of Alex Bannen from that very story.
The exploration of the Artifact and the encounters with the native life forms capture that same sense of wonder but do makes things very bleak. The elements of body horror and hopelessness threaten to overwhelm the reader at points.
Despite this I found the Parasite to be well written with a very tense storyline.
Parasite revolves around the idea of a planet sized living being. Later books introduced other living planets (notably ‘Grimm Reality’ and ‘The Crooked World’) so there is a very good chance a group of PCs might also encounter one.
Adventures based around planets like the Artifact will require characters with good survival skills. Half of the challenge will be understanding the eco-system and recognising it for what it is.
This can be a real opportunity to create intriguing alien life forms for the player characters to encounter. Our own natural world is a great inspiration for this, with many creatures lurking in the dark corners of the Earth that appear to be like something out of science fiction already.
It is important to decide what the purpose of the adventure will be. If it is just about survival there must be something that keeps the TARDIS away from them, making the recovery of their time machine their ultimate goal.
The adventure could be focused on one or more factions attempting to exploit the living planet. Are the PCs trying to protect the world or the new arrivals?
The planet could be the villain of the piece. As in this story the planet could threaten the lives of billions unless the PCs can stop it. This raises ethical questions about destroying a species which is not truly evil, just destructive.
In the background is Elysium system, populated by the descendants of stranded colonists from Earth. The Artifact represents their first opportunity to get home for centuries, although each faction has a different motive for wishing to do so.
Exploring how cultures developed amongst colonists can be an interesting basis for an adventure. If those colonists still want to reach Earth and are close to achieving the goal the player characters could find themselves in the position to decide whether they succeed or not.
Do they decide that the colonists are worth helping? Are they noble with pure motives or do they wish to conquer and exact revenge for their abandonment.?