A well-meaning but hopelessly inept mother (Charlize Theron: Monster, who also produced the film) abandons her 11-year-old daughter (AnnaSophia Robb: Jumper) with her even more incapable brother (Nick Stahl: Sin City) while Mom goes off to do, well, we don’t know what. That kind of untidy loose end — which is meant, I suspect, to represent the messiness of real life — is part of what lends this visually impressive but naratively underpowered film its sense of not enough there being there. The performances are uniformly finely drawn: although Theron is barely onscreen for much of the film, the strange little triptych of a disfunctional family is instantly authentic, and Robb — who is an astonishingly mature actor for age — and Stahl develop an absorbing onscreen relationship both as their characters and as performers working against each other. But the story is lacking both a historical context — we don’t know enough about the childhood of Stahl’s James to really appreciate the surprising act the film culminates in — and a compelling reason for being told at all in the present moment. (The script is the second feature by Zac Stanford, who wrote the equally intriguing but equally deeply flawed The Chumscrubber a couple of years ago.) This is particularly a problem for a tale that’s meant to be about a dark past lighting a way — or not — to a dark future. First-time director William Maher, who’s mostly been a visual FX specialist prior to this, tries to make up for that with a muddy gray palette meant to infuse a grim emotional shabbiness, but all it leaves us with is a film that is ugly in a futile way instead of a consequential one.