On Friday, April 4, at 9pm central time, Kara Thrace will lead Battlestar Galactica to its end. And one of the best science fiction shows---one of the best television shows---will begin its final season.

The producers are saying there will be no standalone episodes. This season will be one long story arc that will bring everything to a close. They're not going to make compromises to attract new fans. This season is for the people who are already fans, and it will be the season we've been waiting for.

(If you're a fan, but you're having trouble remembering how we got to where we are, check out this awesome recap that packs everything that's happened into only 8 minutes and 17 seconds: What the Frack Is Going On? The only stuff missing is from Battlestar Galactica: Razor. If you want to know what happened there, you'll have to buy it.)

Two big mysteries remain: Who is the final Cylon? And what's up with Earth? I have a few theories about both of these things.

Regarding the final Cylon, we can use our knowledge of Cylon reproduction to rule out Karl "Helo" Agathon. Cylons are mating with humans because they can't reproduce by themselves. Helo has had a child with a known Cylon, Sharon "Athena" Valerii, so Helo can't also be a Cylon.

Similarly, Calley can't be a Cylon because she's had Chief Tyrol's son, and he was just revealed as one of the final five Cylons.

I think we can also rule out Lee "Apollo" Adama. Admiral Adama is his father and knows he was born of woman. I suppose the real Lee Adama could have been replaced by a Cylon copy, but there's no evidence the Cylons have ever replaced existing humans. They masquerade as humans, but they are unique beings with histories and destinies of their own.

On the other hand, we just found out that Colonel Tigh is a Cylon, and that has some strange implications. Adama has known Tigh for a long time. Therefore, either the humaniform Cylons have been around a lot longer than we've been lead to believe, or the real human Saul Tigh was replaced by a Cylon copy at some point. So maybe Lee was replaced too.

Given the four Cylons revealed at the end of last season---Chief Tyrol, Colonel Tigh, Tory Foster, and Samuel Anders---the fifth Cylon really has to be one of the major characters. It would be a real letdown if Felix Gaeta or Anastasia Dualla turned out to be a Cylon.

(Unless the final Cylon has superpowers or something else to set him or her ahead of all the others. Dualla's so exotic looking that if she sprouted wings and turned into a Cylon bitch destroyer...that would be cool.)

The most obvious answer is that Kara "Starbuck" Thrace is a Cylon. She's been hearing prophecies about her destiny for a while now, and she's been seeing the Eye of Jupiter all her life. And of course, in the last minute of the last season, she came back from the dead. Cylons do that all the time.

And just because it's so obvious, I don't think Kara is a Cylon. If she was, it wouldn't be a very dramatic revelation for the final season. Pretty much the same thinking applies to Gaius Baltar.

If you don't like my scriptwriting meta-reasoning, I also have an in-script reason for Kara: It's true that Cylons return from the dead, but Vipers don't. Kara died because she was flying her Viper in a hazardous environment and it exploded. When she returned, however, she returned flying an intact Viper. I don't know how Kara Thrace returned to life, but it wasn't Cylon resurrection. It was something else.

(I guess she could have awakened in a vat of goo in a Cylon resurrection ship and been given a Viper that the Cylons had captured. We know they had a captured Raptor, so why not a Viper? Still, I like my theory better.)

I don't think Admiral Adama is a Cylon for two reasons. First, the Admiral-Adama-is-a-Cylon twist is just a little too obvious. Second, if Bill Adama is a Cylon, then Lee is a Cylon-human hybrid, meaning that Sharon and Helo's child Hera isn't the first one. And if Lee is a hybrid, you'd think he'd have visions or something.

On the other hand, the show makes a really big deal about the Cylon-human hybrids, but the producers will have a hard time showing us why they're important unless one of them is grown up. Maybe that's Lee after all. And for a guy without much personality, he certainly has been at the center of a lot of important events.

(It's tempting to make something of the fact that in an early episode the Cylon named Leoben told Lara Roslin that "Adama is a Cylon." He didn't say which Adama either, so it could be Bill or Lee. However, we later learned that the main Cylon models don't know anything about the final five Cylons. That doesn't mean one of the Adamas isn't a Cylon, but it does mean Leoben didn't know.)

That leaves Lara Roslin. She rose to power because of the Cylon attack on the colonies, and she has unexplained visions. In the final episode of last season, she had a dream which she later finds out was a shared vision with Sharon and Caprica, both of whom are Cylons.

For the record, that's my prediction. Lara Roslin is the final Cylon.

(Supposedly, one of the producers has claimed that the final Cylon does not appear in the promotional poster pictured at the top of this article. If that's the case, then the Cylon is a minor character after all, like Gaeta or Dualla or maybe even Sagitaran rebel Tom Zarek. In that case, I vote for Romo Lampkin, the mysterious lawyer who came out of nowhere to prevent the execution of the Cylon chosen one, Gaius Baltar.)

As for Earth, I have some ideas. But this is too long already, so those will have to wait for another post.

If you want a real glimpse of the final season, here's the sneak preview.