Carole Segal, Sci Fi Channel
Katee Sackhoff stars as Starbuck and Jamie Bamber as Apollo.

Tonight marks the beginning of the end for "Battlestar Galactica" — the fourth and final season gets under way.

And it's a bittersweet moment for fans.

There's excitement because we're finally going to start getting answers to the cliffhanging questions we were left with when Season 3 ended more than a year ago.

(However, don't expect a whole lot of answers in the Season 4 premiere, which airs tonight at 8 and 10 p.m. on the Sci Fi Channel.)

There's anticipation because, with this being the final season of "Galactica," we're going to be getting not only answers but a resolution to the story lines.

(Obviously, the producers/writers haven't given anything away. But I have confidence that they'll do some- thing that will satisfy the loyal fans.)

There's sadness because TV's best sci-fi show — one of TV's best shows, period — is going off the air.

But that's tinged with gratitude that "Battlestar Galactica" wasn't just stretched out beyond its logical life span simply to make more episodes.

I can't tell you much about tonight's episode for two reasons. First, I don't want to ruin it for you.

And, second, I don't altogether understand what the things that happen really mean. Let's just say that, yes, four of the longtime crew members do discover that they're not human, they're Cylons.

(You know — the race of robots that pretty much exterminated the human race back when the show began.)

At least they think they are. (I'm hedging my bets there. We've been surprised before.)

And, yes, Starbuck (Katee Sackhoff) is alive. Even though we saw her Viper explode and it seemed there was no possible way she could have survived.

Is she back from the dead? Is she a Cylon? Is she a clone? Has she really been to Earth?

We'll have to stay tuned to find out.

And after we get to the end, we're going to go back before the beginning. Sci Fi finally gave the go-ahead to the long-anticipated "Galactica" prequel. The two-hour TV movie "Caprica" goes into production in the spring, and if it does well it will become a weekly series.

Set 50 years before the events in "Battlestar Galactica," it "follows two families — the Greystones and the Adamas — as they grow, compete and thrive in the vibrant world of the 12 colonies." It will also reveal the origins of the artificial intelligences that eventually became the Cylons.

Will it work to show the beginning when you know the end? If we look to the example of "Star Wars," there's plenty of room for doubt.

But, again, we'll just have to stay tuned.