Season 15 (!) opens with this four part story that was written by Terrance Dicks, that seems to have a bit of that Who Goes There, The Thing From Another World vibe going on in it. This story aired from 3 September to 24 September, 1977.
It seems something has crashed into the sea surrounding a remote lighthouse and is now stalking the three men who live and work there. There’s Ben (Ralph Watson), Vince (John Abbott) and Reuben (Colin Douglas), and each one may fall victim to this strange threat, that can interfere with the lighthouse’s power, unless the Doctor (Baker) and Leela (Louise Jameson), newly arrived in the TARDIS, can figure out what is going on.
Things go from bad to worse when a fog rolls in, effectively sealing them in and aiding to a rather claustrophobic atmosphere, that becomes increasingly crowded when a ship flounders on the rocks, and the survivors must take refuge with the Doctor and the others in a lighthouse that seems increasingly under siege.
The bodies begin to pile up, or do they, as some people thought to be dead are seen again. Leela does her best to try to hunt down the threat, while the Doctor simply tries to puzzle out what is going on, what is killing these people, and who can be trusted.
The more the Doctor discovers, the quicker he learns what is really going on here. The presence in the lighthouse is a Rutan, the much heard about, but rarely seen mortal enemy of the Sontarans. It seems this Rutan, who in his original form, looks like a moving green jello mold, is the scout of an approaching mother ship, who plan to use the Earth as a base in their conflict with the Sontarans.
The Doctor of course will have none of that, and works to find a way to stop the approaching mothership, as well as the Rutan who is stalking the survivors inside the lighthouse.
As a four-part story, this one seemed to be just the right length, it set-up the story, had time to bring in some interesting character, as well as moving the plot along, and had some great moments. The fourth part is truly the best though, as Leela faces off against the Rutan, letting her warrior side out, and even the Doctor isn’t averse to using violence in this situation, causing the creature lots of pain and damage as he tries to stop the threat of invasion.
This one was a strong way to start the season, a good story, great moments, and an almost iconic location. next time though, there will be the introduction of something even more iconic, in terms of the series, as the Doctor and Leela encounter The Invisible Enemy!