Gwen Cooper is your average London beat cop in love with a normal but bighearted lug, but once she's absorbed into the bizarre world of "Torchwood," her relationship with normalcy will forever be tainted.

"Torchwood" is an anagram of "Doctor Who," BBC America's mind-blowing sci-fi adventure, and has been name-checked on that show as a shadowy, possibly sinister organization. In tonight's premiere of the spinoff series, Gwen (Eve Myles) is shocked to see Torchwood in action - its agents briefly revive a dead man - and soon thereafter insinuates herself into this quixotic agency.

Torchwood, you see, employs technology borrowed or pilfered from space aliens in order to solve crimes or perform whatever services or achieve whatever means it sees fit. It's run by the charismatic American Capt. Jack Harkness (John Barrowman), who, records suggest, died in 1942, but who, in fact, cannot die. "I've got a surplus of alive," he tells Gwen.

He and his crew incarcerate and stop crime sprees by marauding, throat-eviscerating aliens, sexually randy space gases, alluringly violent cyborgs and all manner of things Gwen (or the rest of us) could scarcely imagine.

"Torchwood" was created by Russell T. Davies, who punched up the long-running "Doctor Who" series into a spectacularly imaginative and urgent enterprise. This show isn't quite as routinely cheekily apocalyptic, but it's still inventive, entertaining, chockablock with oddball gizmos and menaces alike; one of the latter may prove to be Torchwood itself.

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TORCHWOOD 1/2

>What: "Doctor Who" spinoff: Special investigators use alien technology to solve bizarre crimes.

>Where: BBC America.

>When: 6 and 9 tonight; also 2 p.m. and 10 p.m. Sundays. Also Mondays at 4 p.m. and 7 p.m. on HDNet, beginning Sept. 17.

>In a nutshell: Inventive fun.

David Kronke, (818) 713-3638 david.kronke@dailynews.com www.insidesocal.com/tv/