Popularized by corny big-screen script successes such as Nacho Libre and The School of Rock, White returns to his dark comedic roots in his directorial debut of Year of the Dog, a project more reminiscent of his script for The Good Girl.,Molly Shannon barks, but doesn’t bite hard enough in Mike White’s latest dramedy Year of the Dog.

Popularized by corny big-screen script successes such as Nacho Libre and The School of Rock, White returns to his dark comedic roots in his directorial debut of Year of the Dog, a project more reminiscent of his script for The Good Girl.

Shannon plays Peggy, a middle-aged, socially defunct shut-in who derives her only sense of happiness from the company of her steadfast dog, Pencil. The “Saturday Night Live” (“SNL”) alumna certainly delivers as the 40-something secretary motivated solely by canine affection. Shannon offers an effective combination of past “SNL” characters, particularly the discomfited nature of Superstar’s Mary Katherine Gallagher.

She has few caring friends, save for Layla (Regina King), who offers a few laughs. Peggy’s general aloofness toward marriage and relationships is affirmed by her inability to relate to her dull-witted soccer-mom sister-in-law (Laura Dern).

Despite Peggy’s relentless attempts to establish herself as independently thriving, she too easily falls doormat to all those who surround her. Hence, she relies upon her dog, the only living creature capable of giving her the love and respect for which she yearns.

Peggy’s life, en route to nowhere, takes an unexpected turn after the abrupt health decline and eventual death of her beloved pet. A strange series of events ensues after Pencil is found near death in the backyard of neighbor and soon-to-be arch nemesis Al (John C. Reilly).

The suburban super-hermit breaks out and begins a journey of self-discovery, firmly embracing her uncanny love of animals. Plunging headfirst into the vegan world, she proceeds to become a poster child for a dog adoption agency.

She befriends the earth-centered, ambiguously gay Newt (Peter Sarsgaard). He becomes a source of guidance in addition to the protagonist’s temporary love interest.

Peggy begins to enjoy living, and through her blatant love of animals, adds a sense of meaning and purpose to all that she does. Amidst all of these major changes, White’s humor continues to poke through sporadically.

The first hour of the film does not disappoint. The message is memorable, and the acting is genuine. White’s sharp wit accompanied by Shannon’s awkward candor keep the audience afloat without drowning the underlying theme of self-discovery. Moreover, the film itself is a pet lover’s delight, chock-full of canine abuse outcries and plugs for animal rights.

However, as the film moves into its final scenes, White proves he still has not remedied his Achilles’ heel-successfully ending his films.

Just as in The Good Girl, the climatic build-up just doesn’t meet the falling action. Shannon’s character takes a turn for the worst, and succumbs to some poor decision-making.

Perhaps Peggy’s willingness to shelter more than a dozen dogs in her neat little home would have been more credible had she not later broken into her neighbor’s garage and threatened his life. Though Peggy is relatable to the fragile human condition in many ways, her fanatical tail-spin leaves the audience disconnected and confused. Ultimately, the laughter stops, and general befuddlement begins.

The film’s saving grace is Shannon’s impressive and thoroughly comedic performance. Despite the murky plot strategy, Peggy’s character defends the social shortcomings of all people.

Unfortunately, White’s screenplay just couldn’t throw his cast a bone.