If Eureka 7 was made in the ship-on-the-run, war-and-politics mold of Gundam, its sequel is modeled—at least in its first two thirds—after the cerebral monster-of-the-week series that proliferated in the wake of Evangelion. For most of its run, Eureka 7: AO trots out a new Secret every episode and sends Ao and his Generation Bleu comrades out after it. As the episodes run through their familiar repetitions, ongoing concerns emerge: Ao's origin and relationship with his parents, Eureka's fate, Elena's warped mental innards, Fleur's relationship with her father (President Blanc of Generation Bleu), Truth's nihilistic campaign, the machinations of the various alternate-Earth nations, Naru's transformation at the hands (or microbes) of the Scub Coral. It's all very complicated and often annoyingly cryptic, even more so as the series layers on the time-tripping, universe-rupturing, reality-twisting sci-fi.

Mind you, there's nothing wrong with that strategy. Classics major and minor have been forged in the same mold. And the show's mixture of full-bore mecha action and coyly arranged puzzle-pieces certainly keeps your attention, even when the episodes' individual content doesn't. But there's no shaking the sense that the show is using its enemy-a-week structure to while away the time until it can figure out what the hell to do with all of those ongoing concerns. There's a messiness to the series, a whiff of randomness and undirected improvisation in its plotting, that recalls Evangelion and its ilk less than it does the disordered twists of BONES' own Xam'd.

Unfortunately AO hasn't Xam'd's boldness, that streak of madness that allowed it to throw aside sensible plot progression and go ricocheting in new and weird directions every couple of episodes. Instead AO remains entrenched in its Generation Bleu milieu, sending Ao on repeated sorties and dropping hints predictably along the way.

That wouldn't be such a problem if it didn't mean that the show's irritating elements persist longer than they should. And by that, I mean that Truth is allowed to live for way too long. Truth is one of those awful villains who are both uninteresting and horrendously annoying. He spends the bulk of the series running around destroying crap for no discernable reason, wreaking havoc and sowing chaos while posing like a pretty boy badass and spouting portentous nonsense about the "truth of the world." He's essentially a visual-kei shojo villain, unleashed in a shonen mecha series.

Eventually, though, the status quo does give way. Actually, it's pretty roundly demolished—specifically during the advent of the Quartz Gun in episode 16. (Though it's a full seven episodes before that leads to Truth getting what's coming to him.) What follows is a massive rearrangement of AO's established world order, as assumptions are challenged, alliances broken and forged and re-broken and re-forged. The characters' relations are changed, sometimes radically, and often with heavy-duty emotional consequences. The show's episodic crutches are thrown aside, and cataclysmic changes start to wrack the cast and their world.

Unfortunately, all that change is something of a mixed blessing. To be sure, the series is infinitely more interesting in its final third. But it's still a mess. All that bold movement never seems to lead much of anywhere: wasting time on unimportant subplots, swapping characters' allegiances for no reason, and generally just giving the impression that the show has no idea which direction is the right one to go.

And it doesn't help anything that the final third's driving force is the Quartz Gun, which is essentially a multiple-use reset button. While the series does some intriguing things exploring the consequences of using a world-altering device, the Gun's convenience robs the show of a lot of tension. It's hard to get really worked up about oncoming events when you know that they're malleable after the fact. Likewise, the aforementioned heavy-duty emotional consequences are lethally undercut, made cheap and ephemeral by the eminent reversibility of the show's events.

It's almost miraculous that anything of lasting quality emerges from all of that flailing. But several somethings do. If you're willing to follow the series' time-travelling convolutions right to the end, the series' main emotional threads make, if not perfect sense, a surprising amount of it. Iron out Eureka's knotty timeline and you find a deeply tragic tale of a mother (and eventually, a father) doing her desperate best for her child, even if it means warping the space-time continuum and casting herself into the temporal void to do it.

Likewise, if you keep proper tabs on what the reality-hopping nonsense means for Elena, you are treated to a surprisingly affecting portrait of an alienated girl using inexplicable events to give meaning to her alienation. Indeed, throughout the time-bending conniptions used to weld the show's earlier events together, it's the cast that provides whatever pleasures are to be had. Fleur's bond with her deceptively kooky dad puts real force behind one of the plot's full-force gut punches. Elena's personality issues add sometimes scorching intensity to a few of the later twists. Eureka and, yes, Renton's love for Ao adds emotional resonance to the sci-fi muddle of the finale. And Ao's behaviorally suspect pet sloth is just a joy on every level (hey, sloths are characters too).

The problem is that almost all of those pleasures—sloth gags aside—are loaded into the final third, and usually without the groundwork, or at least the forewarning, necessary to optimize their effect. Instead they come in out of nowhere, and often leave the same way (ushered out, in some cases, by Quartz-Gun schisms in the characters' realities).

Throughout all of this messiness, through repetitive missions, meaningless villain rampages, multiple plot resets, tortured sci-fi explanations, and fleeting moments of bittersweet affect and dark power, BONES makes damned sure that AO looks consistently great. Bones and director Tomoki Kyoda bring the same ravishing level of detail and thrilling fluidity of action to AO's reinterpreted Earth setting as they did to Eureka's otherworldly one. The mecha throwdowns are highly effective showcases for the studio's vaunted production values, as well as Takehiro Ishimoto's ridiculous (but cool!) transforming mecha designs. The displays of technological magic are gloriously showy (especially the Quartz Gun), and the battles cogent and at least nominally sound in their strategy.

AO's world, for its part, is one big advertisement for the art department, especially Generation Bleu's preposterous mountain-valley mecha fortress. Hiroyuki Oda's designs are crisp and attractive, with a crucial facility for emotional heavy lifting. Kōji Nakamura's score, in the meantime, hangs around being eclectic and reasonably attractive without being annoyingly intrusive, and adds some right nice vocal highlights to boot. Some of the later fights might get a little sloppy and insensible, but overall AO is never less than beautifully executed.

With most of the show's charms front-loaded into the cast (unless, that is, you count triple-tiered time travel paradoxes as charms) there's a good amount of pressure on Funimation's English cast to perform. They don't exactly outdo themselves, but they don't underperform either. The dub is pitched straight down the middle in pretty much every way imaginable. It is cast conservatively, performed serviceably, and scripted with roughly the right proportion of fidelity to free-spiritedness. Jad Saxton doesn't handle Elena's personality shifts with quite the schizophrenic ferocity that Chiaki Omigawa does, and President Blanc's trio of Okinawan underlings lose some of their bumbling charm, but otherwise it does what needs doing, and really, what more do you want?

Each of these sets comes with a full complement of textless openings and endings (which is quite useful in the case of OP/EDs where the credits cover part of the in-episode action) and commentary tracks. The commentaries are dub-centric, with participation from most of the English cast a goodly part of the crew. They vary in energy level and educational value, and are probably most useful for getting to know your favorite voice talent. To that end, watching them squirm in set two's video commentary is most instructive.

Given its decidedly mixed quality, how badly you need to see AO will be mostly a function of your attachment to Eureka 7's central couple. For all of AO's little joys—and make no mistake, there are many, even if they aren't exactly evenly distributed—the biggest and most enduring is simply seeing Eureka and Renton, grown up and still being awesome together. It may not be for long, but it's worth it. If that alone isn't enough to get your wallet out, then it's best to forgo AO altogether.