You can’t help but regret Jessica Simpson’s decision to pass on the title role of Aquamarine: Playing an inbred, half-naked sea nymph would have been the perfect follow-up to her turn as an inbred, half-naked mountain nymph in The Dukes of Hazzard. Then again, the burden of carrying Simpson’s pop-icon pretensions might have forced Aquamarine to collapse of its own weightlessness. Affable, synthetic, and 100 percent girly, this beach-blanket renovation of The Little Mermaid boasts (thanks to Simpson’s withdrawal) a virtually unknown cast and (courtesy of Alice Hoffman’s novel) a plot so flimsy that merely to recount it is to kill it. Suffice it to say that seventh-grade bosom buddies Hailey (pop minidiva Joanna “JoJo” Levesque) and Claire (Emma Roberts) are devastated at the thought of being separated. They awake one morning to find, lurking in a swimming pool, a strangely tawny sea creature named Aquamarine (Sara Paxton) who has waterproof eyeliner and a penchant for expressing herself in expletives along the lines of “barnacles!” and “bullshark!” Aquamarine has three days to get cute lifeguard Raymond (Jake McDorman) to fall in love with her, and if Hailey and Claire can make it happen, then their scaly pal will keep Hailey’s mother from moving to the other side of the world. Or something like that. Any further questions must be referred to the film’s intended audience—which the day I went consisted largely of Girl Scouts and their enablers. The surprise, at least for those who fall outside the cookie-pushing demographic, is just how painless the whole business is. Director Elizabeth Allen seems genuinely interested in the covalent bonds of adolescent girls, and she’s found in Levesque and Roberts a pair of refreshingly unslick heroines—and in Paxton and McDorman two actors who would qualify as prom royalty in any ecosystem. Nothing in this exceptionally modest fantasy will make you want to throw out your Hans Christian Andersen collector’s-edition DVD box set—or even your VHS copy of Splash. But as biodegradable entertainment, Aquamarine at least has the benefit of respecting the yearning and confusion of its consumers. Oh, and no one humps a car, either.—Louis Bayard