Another super-powered character hits the screen in “Fast Color,” but though she’s both female and African-American, it’s doubtful that the movie will take in enough cash at the boxoffice to have covered the catering costs for pictures like “Wonder Woman,” “Black Panther” or “Captain Marvel.” That’s understandable, because while the film is an intriguing post-apocalypse feminist parable, it’s also rather sluggish and bland.

The protagonist is Ruth (Gugu Mbatha-Raw), a twenty-something on the run in an America forced to go back to basics because of a prolonged world-wide drought that’s made water a precious commodity. The reason for her desperate effort at concealment is not that she’s a drug addict—though she is. As an episode at a rundown motel shows, she’s possessed of a unique power, setting off earthquakes when she suffers seizures (something her drug use was intended to forestall).

The quake leads to her being befriended by an apparently sympathetic salesman named Bill (Christopher Denham), who turns out to be a government scientist intent on bringing Ruth in. She escapes him, however, and makes her way to her childhood home, a remote ranch where her mother Bo (Lorraine Toussaint) has been raising Ruth’s daughter Lila (Saniyya Sidney) in her absence.

The homecoming is not an entirely happy event. Bo is concerned that her daughter, who claims to be clean, will revert to her old ways, and while Lila is not averse to getting to know her mother, it will be a difficult process for them both. Nevertheless all three agree to try to overcome their reservations and seem to be making process toward reconciliation—at least until the local sheriff (David Strathairn) arrives to tell them that Ruth’s pursuers are at hand. Why he is so concerned for the family’s safety brings a revelation that will hardly come as a surprise.

The story’s larger reveal is that it’s not only Ruth who possesses extraordinary powers. So do Bo and Lila, though theirs are of a more benign kind, involving the ability to separate things into their individual molecules and then rejoin them into their original forms. This family inheritance—on the female side alone—will be fully explained only in a final confrontation with the federal authorities, after Ruth has seen the aurora-like colors in the sky that apparently represent the full realization of her special talents. With that will come an event that presages a new era of hope for humanity, one marked by the acceptance of the strength and wisdom that women have long possessed but been compelled to keep hidden.

In truth, “Fast Color” works better as a fable of female empowerment than as a science-fiction tale or an apocalyptic thriller. That’s not to say that the visual effects aren’t nice, in a low-key way, or that Hart doesn’t stage the action sequences decently enough. But the film is too small-scaled to generate a sense of awe (though the matter-of-fact depiction of a parched world fashioned by Hart, production designer Gae Buckley, costumer Elizabeth Warn and cinematographer Michael Fimognari is well-done), and as edited rather desultorily by Martin Pensa it never manages to be truly suspenseful as a chase film.

It does work better, however, on the more intimate level of family drama. Mbatha-Raw, Toussaint and Sidney convince as three generations of this unusual family, and the always reliable Strathairn adds a note of gravity to an underwritten character. Denham makes a persuasively callow villain.

In the end, however, though “Fast Color” has an interesting premise, the treatment winds up feeling a bit tedious and self-important.