This original anime project first streamed on Crunchyroll during the Winter season of 2010 under its untranslated name So-Ra-No-Wo-To, but now Nozomi Entertainment is making it available in DVD form in a deluxe complete collection. “Complete” is the operative word here, too, as this collection includes the original twelve episodes, an alternate version of episode 1 (which only differs by actually using the series opener and showing the credits during it rather than the opening scenes), and two full bonus episodes: “The Sound of the Sky – Dream's Horizon,” an episode listed on Crunchyroll as a special and here as episode 13, and “Drinking Party – Fortress Battle,” which is listed here as episode 7.5 and is appearing with formal English translation for the first time. Even though the latter episode is a bit edgy due to its inclusion of underage drinking (which may have kept it from being aired on TV), the series is still much better for having both episodes, as the latter amusingly fills in a key gap in the storytelling and the former provides a much more rounded and satisfying conclusion to a series which felt like it wrapped up rather abruptly with its twelfth episode.

The content of the series can be described quite simply: moe military girls go about their daily business and make nice with the locals as they deal with all sorts of light-to-moderate crises. Along the way Kanata learns to play right and various other members of the platoon cope with personal demons: one suffers from survivor's guilt, another has a crush on a man she has mistaken for a war hero, a third is estranged from her prominent father, and the fourth is trying to live down her past involvement in some heinous war-related acts. And that's about it for most of the series. A vague underlying plot which only occasionally even hints at its existence finally starts to gel in episode 10, while episodes 11 and 12 step up the tension dramatically as the discovery of a wounded Roman soldier sets up the series' only major present-time conflict, one which ends in disappointingly predictable fashion. The reflective but also forward-looking episode 13 finishes the series out on a stronger note with a slew of major revelations and a less gimmicky mindset; it is, arguably, the series' best episode.

Although this is not an exclusively moe series, its appeal leans most heavily on its moe aspects, especially the uber-moe affectations of each girl. Fortunately, those are generally effective; there is something endearingly cute about seeing fresh-faced Kanata in a baggy military uniform or watching the three smaller girls (Filicia and Rio, the elder ones, are also decidedly taller) struggle to don and pick up military packs that are, for them, grossly oversized. All five platoon members and the nun they regularly associate with are either exact versions of, or slight variations on, standard moe archetypes and do common moe things, although here we do also get to see what moe characters act like when drunk. (Think of a ridiculously melodramatic war scenario involving squirt guns.) Even the character designs show a clear influence from moeblob series like K-ON!. Those who are not normally fans of moe may struggle to cope with the big chunks of inanity present here.

The series does have at least some other merits, however. For all the cheery spunk that Kanata infuses in, and for all of the light-hearted antics that go on, a certain underlying melancholy permeates the series, a lingering sadness over the technology, knowledge, people, and even land that the world has lost. It is rarely mentioned directly but still present in almost every aspect of the series, such as how the legged tanks seen in a mid-series flashback and at the end are just pale imitations of the “old tech” Takemikazuchi that Noël is rebuilding, the casual mention about how Kanata has never even heard of dolphins, the ruined classroom wing that is part of Clocktower Fortress, or even the tired smile of the blond trumpeter in the opening scenes, and it is more effectively used here than in most post-apocalyptic stories. Nowhere is this more evident than in Filicia's flashback to a disastrous tank mission early in her career and an ensuing “conversation” she has with a long-dead soldier, and nowhere else in heavily moe tiles will you see something like that. The late scenes where the Takemikazuchi finally goes into action, though brief, are worthy of any action-oriented series, and a few moments throughout do effectively punch some emotional buttons.

The series' strongest merit, though, is the meticulous creation and depiction of its setting and the odd way it blends disparate cultural elements. Helvetia is a reference to Switzerland, its region and town names are all French numbers, the language shown on any printed Helvetian document is French, the architecture is generally consistent with older European styles (Seize is supposedly modeled on an historic Spanish city), and vehicles, weapons, and military uniforms are all modeled off of World War II-era German equipment (except for one Roman tank, which is modeled on a U.S. design), but the school wing in Clocktower Fortress is distinctly Japanese, “ideograms” pop up in many places, customs are more in line with Japanese traditions, and the church in Seize is a mishmash of Christian and Shinto beliefs. (A world map shown in one episode suggests that Helvetia is actually part of what used to be Japan, but if so then it is a Japan almost completely subsumed by Western culture.) Romans, contrarily, speak German but have more of an ethnic central Asian look. Binding it all together is an exceptional background effort by Studio Easter, which has done quality backgrounds for a vast array of titles over the years, ranging from City Hunter to Ai Yori Aoshi to the current Hanasaku Iroha. The sense of age, ruin, and decay is beautifully portrayed down to even the smallest and most innocuous details, such as how a stone bridge has been repaired at some point with steel girders, the rubble strewn across a long-ruined classroom, or the consistent background use of blue-on-white image plaques as wall decorations. This is as believable a setting as could be imagined.

A-1 Pictures' foreground and animation efforts are more hit-or-miss. The color scheme used for most of the series give it a bright, warm, and cheery feel despite the run-down settings and some neat coloring tricks are used with the series' opening scene. The mechanical design and CG animation of Takemikazuchi, when finally put into service near the end, is a marvel to watch; this is some of the best legged tank animation you'll see anywhere. Character animation is nowhere near at the same level, however. Character designs mimic K-ON! both in the rough-edged aesthetics they use and in the designs themselves; the platoon members here are essentially tweaked copies of the band members there. A-1 does generally stay away from visual gags beyond a recurring owl, who flattens himself when flustered or observing an embarrassing scene, and throws in only one significant and a few other very minor fan service scenes; the series is definitely not worth watching just for that content.

The regular doses of bugle and trumpet music – including the recurring use of trumpet renditions of “Amazing Grace” – punctuate a fully-orchestrated soundtrack which also features a couple of gentle insert songs. It works well in dramatic, light-hearted, and moody moments but, beyond the trumpet routines, is unlikely to draw much attention. Pleasant opener “Hikari no Senritsu,” which is set to images of the main cast worked into the Flame Maiden legend (a recurring gimmick), opens each episode, while the enthusiastic, ultra-moe “Girls, Be Ambitious” offers a fully-animated ending to all but episode 12. Japanese vocal performances primarily consist of prominent seiyuu exercising their well-tuned specialties, although at least some effort was actually put into making Aisha (the wounded Roman soldier) sound genuinely German.

With this production Nozomi continues its established pattern of providing only subtitled content, although it does offer the unusual option to watch the subtitles with or without honorifics appropriately inserted. Episodes are spread across four thinpacked disks whose cases each feature wraparound bonus art and come in a sturdy artbox. On-disk Extras include brief line art galleries, character bios, and full Episode Previews. (The regular episodes only display the titles of the next episode.) Also included is a booklet which contains a map of Helvetia, assorted staff commentaries, storyboards for the opener and closer, and plenty of bonus illustrations and full-color art galleries.

Ultimately, Sound of the Sky aspires to expand the narrative range of heavily moe titles. While it does succeed at showing that moe can be pulled off in a radically different setting, its success at storytelling is more tenuous. Some of its late plot developments seem hasty and forced, nasty background revelations pop up with only the barest prior hints (if any) that those characters had troubled backgrounds, the warmonger character introduced late is over-the-top to an eye-rolling degree, and the climax is too blunt and oversimplified. The series' premise of staffing a platoon with teen girls is not one of those problems, however, as the idea is not so far-fetched; what would be inconceivable about a country whose population has been depleted by lengthy wars resorting both to female combat soldiers and to soldiers in this age range? (Clocktower Fortress also seems to have a long-standing tradition of housing all-female platoons.) Despite these flaws, the series hits the right note often enough to warrant an overall recommendation.