From left: Mary McDonnell as Laura Roslin, Tricia Helfer as Natalie, Michael Hogan as Saul Tigh, Jamie Bamber as Lee "Apollo" Adama, James Callis as Gaius Baltar, Tricia Helfer as Number Six, Katee Sackhoff as Kara "Starbuck" Thrace, Michael Trucco as Sam Anders, Aaron Douglas as Tyrol, Grace Park as Sharon Valerii, Tahmoh Penikett as Karl "Helo" Agathon, Edward James Olmos as William Adama

Image courtesy of Art Streiber/SCI FI Channel And then there was one. After Battlestar Galactica revealed the identities of four of the show's "final five" human-looking Cylons at the end of Season 3, theories about the last "skin job" burned in fans' brains.

Season 4 of SciFi Channel's re-imagined Galactica begins with even more questions and "what the frak?" moments, and few actual answers about where the show is headed in its final season.

The Cylon revelations in the psychedelic Season 3 finale reinforced the big ideas about religion, war and what it means to be human that have made Battlestar Galactica the smartest science-fiction series on television. The Season 4 opener explores the same brainy terrain.

Galactica's unflinching parallels to current events in Iraq – and executive producers Ronald D. Moore's and David Eick's skill at crafting meticulously orchestrated cliffhangers – earned the show a prestigious Peabody Award in 2006 and have made it SciFi's highest-rated original series to date.

There's a reason for all the accolades: Galactica is top-tier sci-fi television, as gritty and engaging as anything on HBO or at the multiplex. Wired.com got a sneak peek at "He That Believeth in Me," the first episode of Season 4, and offers this (mostly) spoiler-free first look at what to expect when Galactica returns today for its final season.

(Editor's note: If you haven't seen Season 3 and don't want any of its plot twists revealed, stop reading now. Or watch SciFi's eight-minute video that recaps the major plot points of Seasons 1 through 3, and get up to speed immediately.)

Frak is back, big time

Characters spew BSG's signature F word four times in the season opener's first three minutes. But don't expect the Chief to use the expletive any time soon. Aaron Douglas, the actor who plays Chief Petty Officer Galen Tyrol, told Wired.com that he vows never to utter frak on camera. Too bad he's used it at home: While taking pots out of a kitchen cabinet, Douglas says, some kitchenware fell directly on his foot. Gut reaction? "Frak!"

Search for Earth continues

The ragged human colonists are still racing the Cylons to find the lost planet Earth, but are they headed the right way? Direction home: still unknown.

The look that thrills

Galactica's cold, deserted-warehouse cinematography remains in focus, sticking to the blue-tinted production values that have elevated the series visually a cut above its cheesier sci-fi brethren. The show, which won an Emmy Award in 2007 for outstanding visual effects, even got an upgrade: Keep your eyes peeled and you'll notice that in one scene, Cylon raiders do much more than blow up when shot.

Cylon mania continues

The quartet of Cylons-who-thought-they-were humans are still freaked out after learning their true identities, but at least they're no longer haunted – for the time being – by that creepy melody they couldn't get out of their heads at the end of Season 3. Question: If Col. Saul Tigh is resurrected, will he be reborn with his missing eye intact?

No losing the religion

Cued by the episode's title ("He That Believeth in Me"), the deep themes that distinguish Galactica from most genre crap remain in play as religion shifts to the foreground. And the space opera's neurotic relationship dynamic still fires on all cylinders in regard to the question, "Is a Cylon just a Cylon if you've known them all your life?"

Front-burner stories stay hot

Hot-shot fighter jock Kara "Starbuck" Thrace (played by Katee Sackhoff) questions her pretty much unexplainable return. After all, she blew up her Viper and died during Season 3, yet here she is in her cockpit beaming like an angel and telling Lee: "I've been to Earth and I'm going to take us there." Her homecoming? Not so upbeat.

Baltar is reborn

Dr. Gaius Baltar (James Callis), who spirited away from outraged citizens after the tribunal's not-guilty verdict at the end of Season 3, discovers a community that regards him in an entirely new light. Raise your tainted Kool-Aid to the doctor with nine lives.

Seven semi-spoilers from the Season 4 opener follow. Read no further if you're a purist.

Somebody says: "If I found out you were a Cylon, I'd put a bullet through your head."

Somebody wakes up with a naked lover and tries to heal a sick child.

Somebody wakes up President Laura Roslin (Mary McDonnell) by aiming a gun at her head.

Somebody appears to shoot Adm. Bill Adama (Edward James Olmos). Again.

Somebody in manacles says: "I'm not programmed to think about that."

Somebody has a new favorite blanky.

Many, many characters hear voices and see things that no one else can hear or see – but then, you knew that.

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