In some senses this 12-episode manga-based Summer 2013 series is the polar opposite of Attack on Titan, which will likely stand as the year's biggest hit. Whereas the latter will firmly plant its hook and then drag you in hard with its overwhelming style and deeply visceral appeal, this one starts out slowly and weakly, tenderly inserting a hook in the form of the unique nature of its world while its über–moe heroine attracts all of the attention in the foreground. Not until the first arc has finished playing out, capped by a conclusion that may feel rushed but is nonetheless undeniably emotional, will viewers start to fully appreciate just where the appeal of the series lies and how the series will accomplish it. And lest you think that the series has spent all its emotional currency early on, it will keep delivering on its sentiment over and over again, with each story arc having its own share and each arc accomplishing it in different and often unexpected ways. And that is not the only thing that makes this series special, either.

One thing that does not make it special is the deeply moe nature of its central heroine Ai. Her moe appeal is so cynically calculated – small, delicate body; tiny hands grasping a cute shovel; a cute, cosplayable outfit improbable for the setting in which she is raised – that it almost ends up being a detriment instead, as the cutesiness is so completely at odds with the vastly more serious nature of the setting. That this could certainly drive away those averse to moe content on an initial impression is a shame, as the series has so much potential to offer that it does not need to resort to such base appeals.

And aside from the emotional content, that potential shows up most strongly in the concepts which define the setting. Though the basic idea – people don't die when they suffer from some kind of mortal incident and continue to exist agelessly, and no one really seems to know why – seems quite simple, in execution it creates some fascinating oddities and consequences, ones that help make this setting one of the most intriguing worlds in recent memory. How does one distinguish between the living and the dead anymore unless one is a full Gravekeeper (who seem to have the ability to sense the walking dead) or their mortal injuries are apparent? What, precisely, would happen to a society in a situation like this? Would people who are dead be regarded prejudicially and ostracized? Over the course of the series Ai discovers that this is, indeed, the case, and that some of the dead, who either have been kicked out of their communities or have been proactive, have formed their own living-seeming communities where in one case they hide the fact that everyone is dead and in another case they are quite open about it. The latter case, Ortus, is the setting of the series' second story arc (episodes 4-6), and is a veritable metropolis of the dead, one where the living are confined to a foreign quarter and only the dead can gain permanent residence – and for some that have no means, death is a fate that they happily accept in order to earn a place to “live” there. The series also (too briefly) explores the notion that people might actually willingly die in order to emulate the seemingly deathless state of their idol. Or consider that a living person with the truly horrifying ability to slay anyone the person looks at, touches, or speaks to actually has not only a place but also a valuable role in this setting.

And this is really just scratching the surface of what the series delves into. Additional oddities abound, such as the strange nature of the Gravekeepers, the implications of wish fulfillment which may or may not be connected to the whole walking dead phenomenon but are definitely connected to why some individuals have special abilities, and the even stranger nature of the dual-people (and that situation is one that just gets odder the more that they appear and the more that it sinks in for viewers just what, exactly, is actually going on with them). The series, sadly, ends before the mysteries surrounding Ai and her nature is resolved, although everything shown so far indicates that Ai's special nature does not fit into any definition of “normal.” Neither is the truth revealed about how the world really came to be like it is, although these episodes do toss out some vague hints. So much more could be explored here that the series ending after only twelve episodes is frustrating, but that is also a testament to how rich a milieu the series offers.

The setting is hardly the only thing that the series has going for it, either. Each of the five progressive story arcs (three that cover three episodes, one that covers two, and one one-shot) offers situations that may seem vaguely familiar but ultimately do not much resemble anything else in execution. Though the setting is technologically advanced enough to have 20th century handguns and vehicles (albeit few of them appear), this is a time and place where magical things can happen, and the magic which infuses things lends the series a dreamy sense of wonder which can overcome even the occasionally terrible events which happen; if school shootings make you uncomfortable then you should avoid the entire last arc, for instance. The pacing is definitely not perfectly smooth, as the effectively emotional conclusion to the first three-episode arc masks the fact that a couple of story elements well-deserving of greater exploration are dealt with quite a bit too quickly, but the story never fails to deliver clever twists and misdirection and it in no way interferes with the series' ability to generate scenes of sublime beauty.

Key to those scenes is the musical score. Hiromi Mizutani, whose other major works include the Hell Girl franchise, Toriko, and The Wallflower, deftly uses a collection of generally low-key and gently moody numbers to emphasize a tone that promotes mysticism and wonder tinged a little – but only a little! – by sadness. As a result, it helps give a power to the emotional scenes that is mostly free of a sense of manipulation and sappiness. Opener “Birth” does not stand out, but closer “I Sing This Never-Ending Melody” is a melodic number which carries through the tone of the series perfectly and often begins to play out as the final events in each episode transpire. Japanese voice work is decent but entirely unremarkable.

The special nature of the setting and storytelling does not, for the most part, show in the artistic and technical merits. Character designs have very typical anime style points and flair, with youthful female characters typically being tiny in build; not even Ai's trademark cuteness breaks free of the very generic look of all the characters except the dual-people. The only characters that stand out at all are the Princess of Ortus in her protective clothing and the fanboys and fangirls in episode 3, and the latter do so more because they are more punk versions of common designs than anything truly special. Rendering quality and animation are also no better than mediocre, with late episodes in particular commonly relying much too heavily on stills. Background art, while decent by current standards and including an occasional sharp shot, does not stand out. The artistry does, however, make sparing but excellent use of visual effects and does a beautiful job with some of its shot selections. It does occasionally get very graphic but this is never more than a highlight component and at no point does it show any significant signs of fan service. Interestingly, all on-screen text is done in French.

The end of the series is more the end of the most recent adventure and thus does not at all give the impression of a definitive end to the story. Whether or not we will see more remains to be seen, as nothing has been announced by the time of this writing, but there is obviously a lot more story to tell here. Series this thoughtful, high-concept, and original do not come along even every year, so us never seeing an animated continuation of it would be criminal.