BATTLESTAR GALACTICA (Returns Friday, 4/4 10/9c, Sci Fi Channel)

Last March's season finale boosted one of the great shockers in TV history: Four humans -- Col. Saul Tigh (Michael Hogan), Sam Anders (Michael Trucco), "Chief" Tyrol (Aaron Douglas) and President Roslin's assistant Tory Foster (Rekha Sharma) -- suddenly found that they're actually robotic Cylons. When the final season begins, they'll still be in the closet and grappling with their new identities in very different ways, ranging from righteous denial (Tigh) to outright liberation (that would be Tory). A break within the Cylon collective will put Natalie -- yet another version of Number Six (Tricia Helfer) -- in charge of a rebel faction. Back from the dead, Starbuck (Katee Sackhoff) learns of the prediction (revealed in last fall's BSG TV-movie Razor) that she is the herald of the apocalypse and that the humans must not follow her to Earth.

But who is the fifth and final Cylon? "It's going to surprise a lot of people," promises Mark Stern, Sci Fi's executive VP of original programming. "The reveal will have great emotional resonance and will make many things that happened in the first three seasons click into place and make sense."

BSG nuts take hope: The dearth of new material brought on by the writers' strike has revived interest in Caprica, a fully scripted pilot for a BSG prequel that's been sitting around Sci Fi for over a year. Reports Stern: "I just got a call from [parent company] NBC-Universal. They want us to take another look at the project."