- Take one of Joss Whedon's spare Hellmouths, and place under a British city. Say, Cardiff.
- Add one part X-Files and two parts Men in Black.
- Create a Scooby gang including at least one technical guru and one, um, Xander, led by a mysterious, handsome (apparently) stranger with a dark side. If he once died and came back mysteriously immortal, so much the better.
- Give them a Batcave, whose entrance is protected by a Somebody Else's Problem field from Hitchhikers.
- Place the mix into a pre-heated sf universe. (Note: Doctor Who is popular at the moment.)
- Make occasional throw-away references to this show, but do not depend on it.
- In fact, distance yourself from its key fanbase by taking a distinctly adult sf plot (say, Species) and plundering it for Episode 2.
- Before serving, take the name of the parent show and sprinkle the letters over the title sequence.
Enjoy Torchwood. I did.