One of the ways I've come to approach a show that's only okay — not terrible, but not really exceptional either — is to look at the ways it often has great inventiveness in one realm but little ingenuity in another. Stories with great visuals, or at least conceits that lend themselves to being visualized attractively, tend to fall short in other departments because it's easy to think a clever visual is itself an idea on the same level as a strong story. But a strong story, and strong characters to go with it, aren't options — they're the whole reason to watch something in the first place. Karneval doesn't ditch out completely on the story and character side of things, but it leaves them too underdeveloped for the whole thing to be more than a passable diversion. The end result is like being clubbed with a wad of cotton candy: it's too soft, and saccharine, to leave the desired impact.
A shame, too, because I admit to being a fair sucker for stories with gaudy, outlandish, colorful premises. Karneval's idea goes something like this: a secret organization named "Kafka" has tampered with "Niji", a rare breed of creatures and harnessed them for great power, but unfortunately not tempered their work with great responsibility. The resulting monsters, the Naruga, have since run amuck in the world, and it now lies with another team of life-experimenters, "Circus", to put a stop to Kafka's machinations. Circus, as the name implies, has a great cover story: its members travel from town to town in big, glittering airships, and put on Cirque du Soleil-style shows for the locals, while behind the scenes they go a-hunting with their super-powers.
This all ought to be more fun than it actually is in the show, and part of the problem is the way we're introduced to the story: by way of not just one, but two outsiders. The first is Gareki, a don't-give-a-damn cat burglar who's in the process of robbing a mansion when he runs afoul of a Naruga passing as the woman who lives there. The second is Nai, a pale-haired boy caught in the clutches of the Naruga right as Gareki drops in. Gareki is not interested in playing babysitter to anyone, especially not this amber-eyed waif, but Nai's got some curious abilities that seem slightly beyond human ken that come in handy when they find themselves on board a train held hostage by mad bombers.
Circus has also taken an interest in said train, and their operatives spirit the two of them away. Nai's powers are of great interest to Circus, something that causes Gareki to feel something he hasn't had to deal with in a long time: a sense of inadequacy, of no longer being the top dog in the room. The two are also attitudinal opposites: Nai's cheery longing is a constant contrast to Gareki's sullen I-go-it-alone-in-life attitude. But in time we learn another good reason for why Nai is such a source of envy: he's a by-product of a fusion between human and a niji, and it's speculated he was created by "Karoku", a man he remembers distantly (and longs to be reunited with). Too bad Karoku appears to be in with Kafka now, and so any reunion is likely to be a tearful one.
What we have here, then, is two stories: Nai and Gareki, or rather Gareki's uneasy coming to terms with his limitations; and the action-adventure plotline where Circus and Kafka clash. Both could have been interesting, but unfortunately both of them feel underdeveloped for different reasons. I liked that both Nai and Garecki find a place in Circus over time, but the way it's handled doesn't have the level of emotional click that it should. Nai's too passive and Garecki too sullen for them to really be the center of the action, and having the two of them together at the center of the story doesn't make up the difference.
It's a shame, because one of the things about shōjō titles that I find I like is the way they put characters and relationships before plot mechanics or gimmicks. Here, though, the characters and relationships in question feel too thin to sustain the weight of the story piled on top of them. Ironically enough, if Karneval had been more heedless and reckless, along the order of what's hinted at in the first couple of episodes, it might well have worked as the exercise in style it wants to be. But at it's core, it's just too darn nice for its own good.