Featuring the voice of Michael Sinterniklaas. Rating unavailable

Japan has traditionally drawn its life from the sea, but island living is also fraught with fears, as the last decade of tsunami, radiation, government failure, and neighbouring disputes has driven home. And that’s not counting the devastation to our environment, the subtextual story behind Lu Over the Wall, an otherwise mostly cheerful exercise in aquatic anime.

Unlike most PG–rated export anime, this one really is, you know, for kids. It needs to be seen by unjaded eyes, and even then the almost two-hour length and underwhelming plot may be challenging for some adults. Personally, I enjoyed the big fields of flat colour, giving the movie a more abstract look than most Japanese cartoons, which lean alternately toward the nostalgic or the highly technical.

It is harder to relate to the characters, who remain less than two-dimensional. Events nominally centre on moody high-schooler Kai, voiced in the dubbed version by French-born Michael Sinterniklaas, who has been both a Teenage Mutant Ninja Turtle and a Speed Racer in his time, off-screen and on-. (A subtitled version is also playing here.) Kai is more a balled-up fist than an actual personality, presumably because his mother moved to Tokyo long ago, leaving him with a grouchy grandfather and a dad who’s more like a nagging older brother than a nurturing parent.

The mop-haired teen is highly expressive with his laptop Garage Band, however, leading to constant entreaties from schoolmates who want to join musical forces with him. The racially mixed Kunio (Brandon Engman) is into Yuho (Stephanie Sheh), but she likes Kai—not that it matters much to him, or to the movie. It’s more concerned with the merfolk who, legend has it, settled in the harbour of secluded Hinashi Town because of the towering “shadow stone” that protects their waters from the sun’s harmful rays.

Anyway, these creatures (spoiler alert!) are real, and highly attracted to music. And one wee mermaid in particular, nicknamed Lu (Christine Marie Cabanos), leaps out and grows legs, the better to attach herself to Kai. She’s a kind of presexual blob, and it’s unclear what all this means, except that the re-emergence of merpeople—including Lu’s father, a giant, Totoro-like shark—triggers the prejudices of Hinashi’s more backward types, including Yuho’s father, a craven politician. In this aspect, the film resembles Wes Anderson’s Japan-set Isle of Dogs. There are mistreated mutts here, too, although they escape and turn into dogfish. I think that’s what happened.