Created by Josh Whedon, the brains behind “Buffy, the Vampire Slayer” and “Firefly,” the new series “Dollhouse” (8 p.m., Fox) asks questions that go to the heart of individual identity — and for that matter, to the essence of dramatic entertainment. If an experimental subject can take on any identity, does she have any real personality at all? And if an actress offers a series of new incarnations week after week, will she ever develop a character worthy of an audiences’ attention?

“Buffy” veteran Eliza Dushku stars as Echo. For reasons quite murky (think “La Femme Nikita”), she has been recruited by, or sentenced to, a place called the Dollhouse, where her memory is wiped clean on a steady basis and her mind implanted with new memories, abilities, sensations and even neuroses and physical ailments. These new identities enable her to carry out dangerous assignments for mysterious big shots.

In a shadowy subplot, FBI Agent Paul Ballard (Tahmoh Penikett) tries to prove the existence of the Dollhouse, a proposition that seems a tad too far-fetched for his superiors.

Every week, Echo gets a new assignment (foiling a kidnapping, infiltrating a deadly hunting scheme and entering the world of art thieves), only to meet the extremes of her borrowed personalities and to suffer occasional technical malfunctions. Echo’s hard drive seems to seize up at the least convenient moments.

We can all relate.

“Dollhouse” features other “Actives” just as fetching as Echo, making it a bit like a “Charlie’s Angels” send-up — without, of course, the deep character development that marked that series.

Farfetched, sleek, stylish and occasionally silly, “Dollhouse” is a perfect fit in Fox’s high-concept slate of thrillers (“24,” “Fringe,” “Terminator” and even “Prison Break”).

It says something that the network has marooned this thriller on Friday night at 8 p.m., a spot that has been the Bermuda Triangle for Fox series ever since “The X Files.” “Dollhouse” is well worth watching, if it can find an audience.

• In the hour-long “20/20” (9 p.m., ABC) special “A Hidden America: Children of the Mountains,” Diane Sawyer returns to the valleys and hollows of Central Appalachia, an isolated pocket of persistent underdevelopment, crime and social dysfunction that has resisted decades of reformers and a “War on Poverty” and retains a poverty rate three times the national average, soaring drug abuse and the shortest lifespan in the nation.

She spends time with several young people fighting to receive an education and resist violent, self-destructive pathologies that date back decades, if not centuries.

Tonight’s other highlights

• Melinda’s fibs put her in a tight spot on “Ghost Whisperer” (7 p.m., CBS).

• Sarah fights for her life on “Terminator: The Sarah Connors Chronicles” (7 p.m., Fox). New to this time slot.

• A sniper attack may be linked to an earlier case on “Flashpoint” (8 p.m., CBS).

• Matt’s off-field crises compound his tenuous hold on the snap on “Friday Night Lights” (8 p.m., NBC).

• Murder stalks the magic world on “Monk” (8 p.m., USA).

• A shocking verdict suggests jury tampering on “Numb3rs” (9 p.m., CBS).

• Doors close on “Battlestar Galactica” (9 p.m., Sci Fi).