The Beaver (12A)

Mel Gibson is an asset to this tale of redemption.

When Joaquin Phoenix underwent a public meltdown two years ago, it transpired merely to be the raw material for his mockumentary I'm Still Here. Anyone seeing The Beaver would be forgiven for wondering if Mel Gibson has pulled the same stunt, so conveniently does his disgraced public persona nourish his performance as Walter Black, the catatonically depressed CEO of a toy company.

Walter has just been kicked out by his wife, Meredith (Jodie Foster, who also directs the film), when he rescues from a dumpster a raggedy beaver hand-puppet with sceptical, off-centre eyes. He is wearing it when he attempts to hang himself from a shower curtain rail. The beaver peers out at us as Walter lies in a heap in the bathtub, and the old line from Frankenstein ("It's alive!") comes suddenly to mind.

No wonder. Horror films have long featured inanimate accessories acquiring independent life (ventriloquist's dummies in Dead of Night and Magic, a hand in The Hand). Despite one discreetly gruesome scene, Foster holds back on horror, positioning the picture between the slightly worthy "Hollywood does mental illness" tone of Mike Figgis's Mr Jones (the end credits of The Beaver include the message "Depression is a family matter" as well as details of a helpful website address) and the eccentricity of Lars and the Real Girl (man falls for inflatable doll) or Marco Ferreri's I Love You (man falls for keyring).

Soon the puppet is addressing Walter in the abrasive, cajoling cockney of a third-rate Ray Winstone impersonator. "I'm sick," Walter bleats. "The question is: do you want to get better?" rasps the beaver, a specialist in tough love. The film doesn't conceal that it is Walter providing the puppet's voice (there are no "gottle o' geer" moments). Gibson scowls when he berates himself as the beaver, then cowers feebly to deliver Walter's response.

Walter presents himself to his family as a changed man, carefree and personable so long as the beaver is communicating on his behalf, and has a ready-made explanation for how the puppet distances the negative aspects of his personality. Meredith accepts him, even reacting with equanimity when he cradles her in his arms only for the beaver to swoop in for a climactic kiss. The film doesn't sidestep the question of where the puppet goes during sex, but nor does it dwell on the matter: the beaver simply stays on Walter's hand, its mouth opening and closing in time with his decelerating gasps of pleasure, just as it pants along with him when he goes jogging. The film's provocative title decreases in shock value for the audience as steadily as Walter's family comes to accept his unorthodox behaviour.

The script by the newcomer Kyle Killen is comfortingly tidy for a film which argues that we should accept our capacity for emotional chaos. Visual rhymes and recurring symbols work against that idea, imposing order. The dumpster where the puppet is found has an echo in the rubbish pile where a bestselling line of toy beavers ends up after Walter slips from self-help to self-harm. Norah (Jennifer Lawrence), the angst-ridden friend of Walter's equally angst-ridden son Porter (Anton Yelchin), once threw her graffiti artwork in a dumpster, but it was salvaged, just like the beaver - the message being that we are all worth rescuing. It feels contradictory that the same film-makers who bravely refuse to make Walter lovable devote so much screen time to Norah and Porter, who come across as anodyne refugees from a teen confection by John Hughes.

It's typical of Killen's screenplay that Walter is not the only character who dips into ventriloquism or keeps people at arm's length: Porter makes good money dashing off essays for other students, and Meredith conducts business via video conferencing. As with Walter, her career is all fun and games (she designs roller-coasters) even as her life is anything but. Foster and Gibson, cinema's least relaxed actors, are both superb. Her trademark is to stress a breathless syllable by jutting out her face in obscure defiance, while he displays extremes of emotional and physical dereliction - thwarted posture, shoot-me-now eyes, a grey face sagging like a deflated scrotum.

The Beaver is a film with countless problems (how much more desperate it would seem if the characters were not wealthy enough to rent expansive new houses or live in hotels during periods of marital discord). But Gibson, for all his extra-curricular faults, is not one of them. l