Though elements of language and subject matter put “Insidious: Chapter 3” (Gramercy) beyond the appropriate reach of a youthful audience, mature moviegoers will find comparatively little to object to in this run-of-the-mill horror prequel.

Still, if there’s minimal gore on display, there’s equally negligible inspiration.

In this weak franchise’s third installment, writer-director Leigh Whannell aims to provide viewers with the backstory of unassuming but spunky psychic Elise Rainier (Lin Shaye).

Before she got caught up in the occult woes of the Lambert family — the clan around whom the first two films revolved — Elise, it seems, had sworn off dabbling with the afterlife. Unspecified horrors had convinced the newly widowed medium to go into self-imposed retirement.

That all changes with the arrival of high school senior and aspiring actress Quinn Brenner (Stefanie Scott). Dissatisfied with her own attempts to contact her recently deceased mother, grieving Quinn is anxious for the aid of a professional.

Elise reluctantly agrees to help, just this once. But it quickly becomes apparent that, in her amateurish effort to conjure up Mom’s benign presence, Quinn has instead summoned a malignant spirit to her side. This murderous wraith promptly involves the girl in a gruesome auto accident from which she emerges with two broken legs.

The workaday script takes an incidental but welcome stance against suicide

And Quinn’s metaphysical misadventure can be read as warning about the dangers of trying to communicate with the dead.

Yet the movie’s spiritual battle between good and evil is viewed exclusively from a paranormal perspective, with no reference to faith. That’s another good reason to keep the impressionable at a safe distance.

The film contains potentially disturbing scenes of a car accident and its aftermath, occult themes, fleeting references to homosexuality, a couple of uses of profanity, at least one instance of the F-word and about a half-dozen crass terms. (A-III, PG-13).