Rough Magik was pitched as a TV series to the BBC in 2000 (or so). They didn't pick it up, but the pilot episode has been released on DVD and stands alone reasonably well, as long as you don't mind an extremely open ending. It's like watching a movie that sets up a sequel which never comes. I'm sure you've never had that experience.
Rough Magik follows The Night Scholars, a government organization whose job is to keep the cult of Cthulhu (better known here as "Dreamers") in line. Cthulhu, for the uninitiated (eh, who am I kidding? You already know this.) is an ancient alien, sometimes worshipped as a god, who slumbers beneath the Pacific ocean but is expected to awaken and rule the planet again sometime in the future. This is the backstory of H.P. Lovecraft's The Call of Cthulhu, and is explained in about as many words by the protagonist of Rough Magik, Mr. Moon (Paul Darrow). Moon is the kind of cool-headed sociopath that makes a good TV government agent, and he shows up uninvited to take stock of a murder investigation.
The murder in question is that of two children. The culprit is their mother, and she seems perfectly content to confess her crime. She's been having dreams, you see, and they told her what to do. Moon takes one look at the tentacled idol in the corner, and decides to speak with a former Night Scholar, Kenneth Reese Warren (Gerrard McArthur). Mr. Reese Warren, under drugged interrogation, recounts a military operation involving another ancient alien, telekenesis, and personality swapping. The film ends with Mr. Moon reflecting on the possibility that Cthulhu is waking, and that the Dreamers -- who are scattered across the furthest corners of the globe -- will need to be stopped.
Apparently this pilot episode was actually intended to be the second episode of the series, and I can imagine the story unveiling over six or twelve episodes. That's how British shows work; there are far fewer episodes, and they tend to comprise a single story arc. The setup of Rough Magik almost negates a monster-of-the-week format, which would have made this into a British X-Files.
The series as a whole might have been good, but as I said above, I don't like this episode. I've seen it a few times now, and this is the only time I've really gotten the story. I know exactly what the problem is. It's that most of the episode is taken up by Reese Warren's story, told in flashback. These flashbacks are uneventful, boring, and frankly, there's a lot of irrelevant material. The end of the flashback is really interesting and engaging, but you have to slog through twenty minutes of soldiers crawling through mud to get there, but at some point during this part, my brain just shuts off, which is why I've never understood the story before. I've had the same experience watching Jacob's Ladder and Starship Troopers, which superficially suggests that the military bores me, but I've liked enough army movies that I know that's not it.
Still, other people seem to like it. There are some good points, though I wonder how they'd have developed Mr. Moon. He is obviously intended to be the main character, but he isn't given much personality, other than being a ruthless bastard. They also get points for getting the Lovecraftian angle right. It's really too bad that Rough Magik didn't get picked up as a series, but I think they were a little too early. A few years later shows like this one became common and popular.
I don't believe that you can stream this one online (certainly not legally, anyway), but Netflix has the disc, and you can watch the trailer here.