"First a collision, then a dead navigator, and now a monster's roaming about my ship. Well, it's totally inexplicable." So says Rigg, captain of the passenger liner Empress, to the Doctor.
What happened? A freak accident takes place within orbit of planet Azure. The Empress nearly collides with a small ship, the Hecate, while in lightspeed and materializes around the smaller ship so that they have fused together. The nose of the Hecate is sticking into the Empress, blocking the larger ship's access to the power room and passenger deck. The blurred overlap areas, or matter interfaces between the ships, however, are unstable.
Into this situation comes the Doctor, Romana, and K9. The Doctor offers to help separate the ships, something to which both Rigg and Dymond, pilot of the Hecate on a survey contract job, are amenable to. All that has to be done is to recreate the circumstances of the accident: "excite the molecules, full thrust, then full reverse." However, Rigg's navigator Secker, who got them into this accident, is on vraxoin, a highly addictive drug that "induces a warm complacency and total apathy until it wears off that is, and soon you're dead." In fact the Doctor's seen entire planets destroyed by this drug. Secker's then attacked and killed by something clawed. The questions are, who provided Secker with the vraxoin, and what killed Secker? After all, vraxoin can be detected by the Empress's scanning device, and the Empress's route is the milk run from Station 9 to Azure, nowhere else, with no stops inbetween. And who is the mystery man who knocks out the Doctor, then tries to evade him later?
There's also Tryst, a zoologist with a funny accent and really thin trendy rectangular glasses, on a research expedition to preserve rare species on government funding, made difficult by the Galactic recession. With the aid of the CET (Continuous Event Transmuter) machine, he records the flora and fauna of planets on an event crystal that continue to exist in the machine. A simpler way of naming the CET is an electric zoo. However, the lack of a dimensional osmosis damper in the CET means that with the freak accident, the unstable overlap zones affects the dimensional matrix of the machine, meaning things can go in and out of the machine.
Things heat up when two trigger-happy and bureaucratic Azure excise men, Fisk and Costa, try to arrest the Doctor and Romana as the vraxoin smugglers, and someone slips some vraxoin in Rigg's drink.
The cliffhanger to Episode 1 is effective, as a shaggy monster with glowing green appears from a wall panel K-9 has lasered away. And some interesting special effects are used when the Doctor enters the unstable matter interfaces. However, two goofs are apparent. When Della, Tryst's colleague, is shot in the head, she clutches her stomach. Also, Fisk calls Tryst "Fisk" in Episode 4.
Two funny lines from Tom Baker. When the Doctor's cover as an insurance agent is blown, he says, "I wonder why I hadn't been paid." "That's not good enough," says Rigg. "That's what I said." responds the Doctor. Also, he playfully says that Tryst helps conserve species in the same way a jam-maker conserves raspberries.
If one adds a shaggy beard to David Daker (Rigg), one will recognize him as the warlord Irongron from the Who story The Time Warrior. His transformation from an upright responsible captain to a complacent, laughing, apathetic man addicted to vraxoin is good. When someone points out to passengers being killed, the vraxoin-addicted captain says "They're only economy class, what's the fuss?"
The issue of drug addiction is key here, but are the dealers justified in saying of the buyers, "they had a choice"? If it's something dangerously addictive that totally incapacitates a person, as in vraxoin, well, no, but what about something less or not addictive, like marijuana?
Apart from the flaws in Episode 4, Nightmare Of Eden is watcheable, with laudable special effects, but nothing too special.