There's no silver lining to "The Mist" (MGM/Dimension), the technically skillful but relentlessly pessimistic film based on a popular novella by Stephen King.

When an unnatural fog, alive with murderous mutant animals -- including insects, birds and even a giant octopus -- descends on a small Maine town, it leaves a representative sampling of the local population trapped in a grocery store. Prominent among them is courageous but sensible David Drayton (Thomas Jane), who is a movie-poster artist, and his young son, Billy (Nathan Gamble).

As Drayton, aided by plucky store manager Ollie (Toby Jones), does battle with the malevolent critters on the outside, he finds he must also struggle with an equally challenging threat from within. His neighbors have begun to divide into opposing groups, one led by religious fanatic Mrs. Carmody (a darkly intense Marcia Gay Harden), the other by Brent Norton (Andre Braugher), a relentlessly skeptical lawyer.

Can the townsfolk overcome the weaknesses of human nature and unite to defeat their common enemy?

Writer-director-producer Frank Darabont's horror film has the makings of a diverting, old-fashioned monster movie. Certainly, the film's excellent special effects and energetic filming might have combined to make it a sort of earthbound successor to Ridley Scott's "Alien."

But "The Mist" -- in addition to being excessively bloody -- is weighted down with larger ambitions and a larger agenda. As it attempts to analyze everything from social dynamics and religion to the fundamental polarities of human nature, the talky script meanders, the film's pace often slackens and the shallowness of some of the characters becomes ever more obvious.

Mrs. Carmody, for instance, cherishes a wildly inconsistent set of moral values, one that caricatures, and therefore marginalizes, the conservative religious outlook she embodies. Thus she equates men walking on the moon with stem-cell research as violations of God's law and denounces abortion even as she urges her followers to murder little Billy "in expiation."

Jones' character, who turns out to be surprisingly resourceful, helps give the film its moral center, as does retired schoolteacher Irene, played by the venerable Frances Sternhagen, who bravely stands up to the motley crew of obstreperous mutants.

Although the film's conclusion can be read as a morally positive warning against despair, the lesson comes at a harrowing cost. Thus, while the physical mist of the movie's title may eventually pass away, the spiritual obscurity to which it alludes seems destined to endure.

The film contains bloody violence and mutilation, mercy killing, pervasive rough and crude language, much crass language and profanity. The USCCB Office for Film & Broadcasting classification is L -- limited adult audience, films whose problematic content many adults would find troubling. The Motion Picture Association of America rating is R -- restricted. Under 17 requires accompanying parent or adult guardian.

Movies have been evaluated by the U.S. Conference of Catholic Bishop's Office for Film and Broadcasting according to artistic merit and moral suitability. The reviews include the USCCB rating, the Motion Picture Association of America rating, and a brief synopsis of the movie.

The classifications are as follows:

• A-I -- general patronage;
• A-II -- adults and adolescents;
• A-III -- adults;
• A-IV**
• L -- limited adult audience, films whose problematic content many adults would find troubling. L replaces the previous classification, A-IV.
• O -- morally offensive.