The point of Carnival?beyond getting drunk, getting it on, and letting yourself go one last time before Lent ushers in a season of repentance?is to bring everyone together. Sure, some of that coming together involves krewes throwing favors to the begging throngs, like the holdover from feudal times and earlier that Carnival is. But Carnival is primarily a community celebration and a moment when the usual barriers dividing people who ordinarily have nothing to do with one another break down, if only for a little while. Inhibitions and reservations get lowered, with masks and costumes finishing the job alcohol begins. While getting extra points for the difficulty of shooting at least some scenes in the midst of Mardi Gras?I’m just assuming some of those location moments couldn’t be faked?“Carnival Time” captures that spirit beautifully and lets the spirit carry over to the episode itself. “Carnival Time” is one of the best episodes the series has produced, in part because it feels so cohesive and so poignant in the way it lets its characters storylines rhyme against one another, mixing giddy moments with heartbreak and making it all feel like part of the same world, and part of a world bigger than the show itself.

Last week, we left Terry walking with the Pigeon Town Steppers, but this week, he’s all business, and business means making sure Mardi Gras proceeds safely and in an orderly fashion. Protecting and serving is, of course, what police are always supposed to do, but Mardi Gras, and particularly a Mardi Gras after the violence New Orleans experienced leading up to the celebrations in 2007, gives his job an extra layer of responsibility. Whether it goes well or not doubles as a referendum on the health of the city. It’s all about keeping the excesses contained. Terry’s polite when he stops the woman who doesn’t know the ins and outs of where one can flash the crowd without causing any problems and angry when he busts the kid who brings a gun to the Krewe Of Muses parade. But both responses stem from the same impulse if keeping Mardi Gras on track and trouble-free. Nobody carries more weight this episode than Terry, and nobody feels as relieved as he when it’s over. (Not that there was much doubt, but David Morse has proven to be a great addition this season.)

Antoine doesn’t get the Mardi Gras he wants, but he may get the Mardi Gras he needs. Forces have conspired all season to bring him reluctantly, and belatedly, into the world of adulthood and responsibility and they continue their job this week. Without losing his gruff skepticism about the enterprise, he’s clearly become taken with teaching, at least in the moments when he spots the sort of talent that can keep the city’s music alive. He doesn’t get the day of hook-ups he so carefully set up, but he does get a day being a father to his kids. We last see him asleep on the couch as a digital clock announces midnight and the beginning of Lent, and the shot feels significant.

Davis, on the other hand, gets exactly the Mardi Gras he wants, even though it means disappointing Annie. It’s a day of drunkenness and mischief and one in which he doesn’t even worry about his new musical enterprise so much. It works out for him, and it’s fortunate for Sofia that he sticks around (more on that in a bit), but all the scenes of Annie attending Cajun Mardi Gras make it seem like he missed something by not leaving the city for the day. Fascinating stuff, right? I’m not sure what Harley and Annie’s excursion means to her musical education, but just on an anthropological level, I appreciated all the space “Carnival Time” gave to Cajun ritual, from the costumes to the music to the chicken chasing .

Nelson, meanwhile, gets immersed in a ritual a little closer to his new home, joining the Zulu Social Aid And Pleasure Club, donning the blackface favored by the largest mostly African American krewe in town, participating in the parade, and going home with the prettiest parade-watcher he passes. It’s a good day for Nelson and one that brings him ever more tightly into the social network that runs New Orleans, even if he seems to forget any personal motives for the moment. So let’s pause to ask a question Nelson doesn’t seem to be asking: Where is this going? Are Oliver Thomas and others seducing him into going native for the good of the city? Are they making a proper New Orleanian out of a would-be carpetbagger? And if so, will it take? Nelson delights in the city and the pleasure it has to offer, but he still doesn’t seem invested in its well being beyond his own benefit. That tension can’t last, even if he’s yet to realize that. But waiting for him to see it has started to turn his story into one of the season’s most interesting.

Albert’s story has taken a less dramatic turn, but that doesn’t make it any less satisfying to see him returning to New Orleans to lead his tribe, proudly sporting the beadwork Del crafted for him. I’ve loved all the time Treme has spent with that subculture, with its own unique rituals and music, this season and last, and the Mardi Gras scenes don’t disappoint, letting us see Indian celebration in all its splendor. The parade also gives Del the breakthrough he’s been struggling for all season when he hears Indian beats contrasting against jazz licks. It’s not the episode’s subtlest moment, but it is the revelation his plot has been building toward all year. And, besides, I’d listen to an album like that. Assuming, that is, that Del’s not too distracted by his father’s active sex life to finish it. Any theories on Albert’s new friend? Maybe the documentarian?

Another parent and child pair, Toni and Sofia, have a more complicated day. Toni tries to celebrate Mardi Gras just like the family did before Creighton’s suicide, but the harder she pushes, the more Sofia realizes how much has changed, and the harder it gets for her to control her resentment that Toni kept the nature of her father’s death from her. They can leave the stereo playing Professor Longhair like they used to, but it just won’t be the same. Before the day is over, Sofia’s run away, taken advantage of her fake ID, and almost gotten herself into trouble. She saved by Davis, an unlikely white knight in no position to give her a lecture on drinking even if he wanted to but one who won’t stand by and watch others take advantage of her. She’s resisted her mother’s pushing, and in resisting it left her alone to lay some of Creighton’s ashes to rest in the river (in an extremely moving scene). Neither of them can talk about what’s driving them apart, and the longer they wait, the further apart they drift.

Then there’s the temporarily absent: LaDonna shows no signs of getting better or inclination to come home, taking up a drunken, semi-permanent residence in the Baton Rouge house she so long resisted. Janette tries to scrape together a proper Mardi Gras day in New York and at least gets to enjoy some king cake and a meal that renews her appreciation for fine cuisine. And Sonny gets spirited away to do some hard work away from the celebration and its temptations. And, you know what? I think even the Sonny plot worked this week. For the first time I found myself caring whether or not that character got his shit together.

And if that’s not the sign of a superior Treme episode, I don’t know what that is. Well that and an exciting bunch of music sequences, including appearance from Al “Carnival Time” Johnson, whose biggest hit gives the episode its name. Series creators David Simon and Eric Overmeyer penned, and the direction comes from feature vet Brad Anderson. Hats off to all involved. This was an episode that effortlessly brought together the series’ sprawling cast of characters and made their individual stories feel like one big story. The show usually gets that right, but some weeks, it gets it righter than others. I’m more eager than ever to see where the season and the series go from here.

Stray observation

• Just this: