"33", the first Battlestar Galactica episode to hit the air after the success of the pilot miniseries, is a two axe episode.
The first is the axe that hangs over the collective heads of the fleet - the Cylon attacks that occur every 33 minutes as the Colonials are hounded from jump to jump. It's a plotline of excruciating tension as the refugees, strung out on lack of sleep, wait to see if the Cylons will appear again.
Meanwhile, an axe appears over the head of Gaius Baltar - the threat that his (unintentional) treason will be discovered. Sure, there was a moment in the miniseries during the evacuation from Caprica when Baltar was recognized by Helo and feared he'd been outed, fears that turned out to be unfounded. But that's an incident that's quickly put to bed. Here, in "33", it lasts for pretty much the entire episode when he hears a scientist from another ship wants to come to talk to the president about a security breach. And while this threat is resolved when that scientist's liner disappears and is later destroyed after returning, this episode none-the-less sets the tone for Baltar's mindset, for his constant fear of being discovered, that will last for much of the series until the Cylon occupation of New Caprica. At that point, his fear of persecution switches from a past of treason to a new reality of being a collaborator.
Of course, Baltar's got something else distracting on his mind - Six. At this point, so early in the series, there's still a hell of a lot of mystery shrouding her. Sure she spouts a lot of religeous nonsense, but there's nothing at this point to indicate she's some sort of angel. Given Baltar's panicked state of mind, it would seem his own explanation of some sort of combination guilty conscience, active imagination, stress and mental breakdown is at work, or the possibility raised by the imaginary Six herself, that she's the result of some sort of chip she implanted in his brain back on Caprica. Either one of those would have served well throughout the entire series, or better yet, to keep the mystery intact, keep audiences wondering which of those possibilities it was. Instead, as we found out last spring, this Six turns out to in fact be an agent of some grand, non-corporeal entity. But we're not that far yet. At this point, the mystery is plenty good enough, and fairly unnerving in and of itself. Does it constitute an axe over Baltar's head like the fear of discovery does? Not so much, because Baltar doesn't assign any kind of threat to the Six illusion (yet) - at worst, she's a theologically pendantic annoyance; at best, a pleasantly sexy daydream.
"33" is also interesting as an episode because we see Adama and Roslin move into a real working relationship, rather than the mistrust, mutual disdain, and jousting of their initial encounters in the miniseries. When we see them on the phone during the crisis, we see honest, professional discussion and consultation, demonstrating that the writers are giving us more than one-trick ponies who force everyone to make the no-win choice between the politicians and the military like the old series did. These are people who in real life would be worthy of respect and trust.
We also see the relationship between Apollo and Starbuck continue to develop as Apollo figures out what it really means to be in command and to have to ensure that Starbuck follows orders - especially the ones she doesn't like.
"33" gives us another cool element as well - the story of Helo's survival back on Cylon-occupied Caprica. Someone who could have been a throwaway character from the pilot now has a significant plotline. This is important not only because it illuminates more of the Cylons' plan, but also because it answers that nagging question in the back of the audience's mind (a question that was never addressed in the clunky old series): what is life like for those that didn't make it off the Colonies? Here we see what it's like for a person living under an occupation, to be on the run in one's own home, having to maintain hope even though logically there is no real possibility of escape. It's also important because this thread introduces us to the other Sharon, and sets a fascinating dichotomy at work over the course of the season: as Boomer starts to come apart aboard Galactica, Sharon grows into a more grown-up, complex and full personality alongside Helo on Caprica.
"33" reminded me a lot of a moment in the movie (I can't remember if this was in the book or not) High Fidelity, where John Cusack's character talks about the intricacies of making a good mix tape for someone. He notes that you've got to start big to really turn the listener on, then, for the second selection, take it up a notch to maintain the momentum. "33" works exactly like that in relationship to the big start provided by the miniseries. What a great way to get season one of BSG under way.