What is Homeland, exactly? In its nervy, off-beat first season it was a tingly espionage mystery, filled with cool CIA process and some ballsy bits of pulp. (Our heroine sleeps with the man she is investigating.) In its second season, the show amped up the melodrama and turned into a soapy thriller, one that was plenty entertaining but didn't snap with the same crisp sorta-credibility as season one. Lumpy and overheated, season two ended with a bang, a grand set piece that erased some memory of the janky plot contrivances that preceded it. And so we head into season three (premiering this Sunday at 9 p.m. on Showtime) not knowing what to expect. Thriller? Mystery? How about psychological melodrama.

At the start of season three, (I've only seen two episodes, so things could, and likely will, change drastically) everyone is adrift. Nicholas Brody has fled the country, as he's now believed to have blown up half the CIA and everyone's pretty mad about that. Carrie and the rest of the agency are in hot water for letting the attack go down in their own front yard. And Brody's family is reeling from the magnitude of the betrayal, suffering the public's ire in Brody's stead. Brody isn't in the first two episodes, setting us up for some dramatic reveal in episode three that will hopefully kick the season's main story into rollicking motion. But in his absence, Homeland turns inward, drearily examining the crumbling hearts and minds of those staggering around in the explosion's aftermath.

Carrie is a mess, as was to be expected. We get the first glimmers of her resurgent mania in a congressional hearing on the CIA's epic bungle. Tracy Letts, acclaimed Chicago playwright and actor, plays her main antagonist, grilling Carrie with a flat Midwestern smugness dripping with disdain. Carrie and the agency are in some serious trouble here, and Letts's Sen. Lockhart seems coolly thrilled with the prospect that he might be able to dismantle the whole operation and throw everyone involved in the Brody fiasco in prison. These are tense, well-written scenes that hum with first-season sharpness and authority. (And we get the extra kick of seeing Letts spar with his Who's Afraid of Virginia Woolf partner Amy Morton, playing Carrie's CIA-appointed lawyer.) But when the show moves on and starts exploring other parts of Homeland's world, things quickly become muddled and dull.

Well, to be fair, Mandy Patinkin and F. Murray Abraham do stalk around Langley doing some interesting old-timer conniving, orchestrating many people's doom — including Carrie's, to some degree. But beyond that, we're left mired in a lot of psychological somberness that, while welcome on this show in smaller doses, swallows up too much of the early parts of season three. Claire Danes plays Carrie's frantic unraveling beautifully, and scarily; though trembling and drenched in hot, angry tears, Carrie is not simply some weak, hyper-emotional wreck. Her conviction and impetuousness can be dangerous, we know this, and as we watch her spin into a new frenzy, her scenes pulse with dread. That said, the larger arc of Carrie's mental health struggle seems to be wandering in circles at this point. Those watching Homeland looking for a propulsive spy thriller might find all this interior drama a bit repetitive and superfluous.

Though, Carrie's plight is practically a Bourne movie compared to the moody meanderings of our old friend Dana Brody, the mumbly, hair-fondling would-be terrorist's daughter, given a frustrating, almost absurd amount of screen time in the first two episodes. Brody's family has always been the dullest part of Homeland, and any hopes that they might be pushed to the background now that Brody is (temporarily) out of the picture are quickly dashed in the season premiere. Dana gets most of the focus so far (poor Chris is left ignored as always, with no Mike around to make him eggs), returning home from a psychiatric facility following a suicide attempt. She's depressed and confused, and only feels good when she's in the arms of her dreamy psych facility boyfriend. A great deal of the second episode is devoted to Dana's moping and to this new relationship, and unless this twinkly eyed twink turns out to be a secret terrorist, the whole plot line seems like a lugubrious distraction. At the moment, if you described Homeland season three as being about a troubled teenage girl living in Virginia, you wouldn't be inaccurate! Lying by omission, maybe, but not wrong.

There are at least a couple of jangly action thrills in these first two episodes, mostly involving Rupert Friend's shifty, deadly Peter Quinn. He bestrides the moral line of the show with both determination and reluctance, illustrating a troubling ethical ambivalence that this show has been so good at exploring in the past. The introduction of a new character, a young Muslim financial analyst (Nazanin Boniadi) brought in to aid Saul and crew on an investigation into Abu Nazir's backers, brings some new blood to the team, and in the process startlingly exposes some of Saul's cultural prejudices. I like Homeland quite a bit when it's at work. It's when it goes, well, home that it tends to stumble. So far there is not enough of the former and far too much of the latter.

But, as we saw in the first 24 episodes of this odd and discordant series, a Homeland season is likely to radically change in tone and direction every few episodes. So here's hoping that season three quickly gets out of its emotional funk and fixes its eyes back on the target. It doesn't have to shoot straight, but it should at least aim at something other than the floor.