Terminator: The Sarah Connor Chronicles has been on a slow boil of character development... and last Friday, it started to pay off. Big time. There will be spoilers.

Last Friday's Terminator episode, "To The Lighthouse," started off slow and moody, but then it pretty much exploded with action and, more importantly, with revelations.

Sarah Connor decides she can no longer trust either Derek or Cameron, in the wake of the Jesse/Riley fiasco. So she sends them to the wrong safehouse, while she and John go to a lighthouse that only she and her ex, Charley, know about. Meanwhile, Cameron tells Derek that Jesse had been pregnant with his child on that nuclear submarine, but she had a miscarriage. And someone (or something) has hacked John Henry, supposedly the most advanced A.I. on the planet.

Paranoia Doesn't Always Keep You AliveS

I've occasionally chafed at the show's insistence on making Sarah out to be a paranoid psychopath with occasional delusions, but that strand of the story definitely paid off on Friday. In a huge way. Sarah's paranoia leads her to cut herself and John off from their strongest allies, leaving them vulnerable to attack. Sometimes paranoia isn't a good survival trait — even if they really are out to get you. At the same time, Sarah's sense of self-sacrifice leads her to avoid getting her breast lump checked out for far too long — and then it turns out not to be a lump at all, but a tracking device. I really did not see that coming at all. At that point, kick-ass Sarah returns, with the best use of a defib ever. Actually, two of the best uses.

Paranoia Doesn't Always Keep You AliveS

Meanwhile, I'm definitely getting more sold on this version of John, after the most recent couple of episodes. Check out the clip above — he knows Charley is sacrificing his own life for him, and there's nothing he can do about it. All he can do is accept the life of another father figure, one more line in the long list of men who've died for him. And get the hell out of Dodge. The flashbacks of Young John and Sarah in the jungle reinforce quite how much he was learning, from early on, to think like a soldier. Oh, and I liked all the bonding between Charley and John, and Charley trying to help John deal with his grief over Riley's death.

Paranoia Doesn't Always Keep You AliveS

I pretty much always love any time Cameron and Derek have to team up, so that was pretty much pure win for me. And Camron's idea of "teaching Derek a lesson" by making him confront the loss of a child he didn't even know he had. And then later, she rescues him, because he might be useful. Even though Derek doesn't trust or like the pet Terminator, I always feel like Derek and Cameron understand each other in a way that nobody understands either of them. Maybe because they're both from the future.

And then there was all the great stuff around John Henry getting hacked, and how it all plays into Ellison's religious beliefs. First all the talk about John Henry's "daemons," and then his message "Oh God Why Hast Thou Forsaken Me", and finally his "death" and resurrection. Given that John Henry is almost godlike in his abilities, it's pretty spooky.

And then there's the big reveal at the end, that there's another A.I. like John Henry, and it's searching for its "brother." And the other A.I. has ties to Miles Dyson and Cyberdyne — making it a much more likely candidate to be Skynet. Or maybe the two A.I.s, combined, turn into Skynet? In any case, this "brother" A.I. appears to be connected to the people who attack John, Sarah and Derek at the end of the episode. And since it got that tracking device into Sarah's breast, it's also linked up to the people who were running that factory, building Hunter-Killers.

It all seems to be leading up to a pretty explosive finish, and yet almost all of the pieces come out of the slow character study the show's already done on its major players. I can't wait to see how it turns out. What did you think?