They should stock extra-absorbent tissues at the concessions stand for The Blind Side, an engaging if transparent tearjerker of the first water.

Adapted from Michael Lewis' 2006 nonfiction book, it tells the story of Leigh Anne and Sean Tuohy (Sandra Bullock and country music star Tim McGraw), an affluent white couple in Memphis who take Michael Oher (Quinton Aaron), a destitute black teenager, into their home and family.

A refugee from the foster care system, Oher is a withdrawn, mumbly young man carrying a sadness so deep it can't fit even his immense body.

The Tuohys bring him back to their McMansion after they find him wandering the streets on a cold night with only the clothes on his back.

In case you're missing the point that Oher is a pauper swept into the land of plenty, director and script writer John Lee Hancock has him stare at a blown-up Norman Rockwell Saturday Evening Post cover his first night in the house after everyone else has gone to bed.

Fed a steady diet of kindness and material goods by the Tuohys, Oher begins to - you guessed it - blossom.

The Blind Side wisely takes its time before playing its trump card: football. The real Oher was a heavily recruited high school prospect, a lineman who currently plays for the NFL's Baltimore Ravens.

The movie is a kind of My Fair Tackle with a discomfiting racial overlay. Blacks live in weed-strewn projects ruled by crack dealers. Apparently, their best hope is to latch onto a white benefactor styled by Ralph Lauren.

Bullock is terrific as this fable's Professor Higgins. Her Leigh Anne is a mix of Southern decorum and sass, a woman who hides her big heart under a bossy, no-nonsense shell.

Like most of the characters in The Blind Side, she undergoes instantaneous and convenient conversions.

Over lunch, she suddenly discovers that her best gal pals - together they look like The Real Housewives of Memphis - are narrow-minded bigots. No hint of this ever emerged in the thousands of Cobb salads she shared with them over the years?

A quick and implausible on-field pep talk from Leigh Anne (a speech prominently featured in trailers and ads for the film) transforms Michael from a clumsy and passive player into an unstoppable pile-driver.

McGraw, nearly unrecognizable with a clean shave and an Alfalfa part in his hair, is appealing when given an opening, but he's mostly there to hold Bullock's purse.

The scene-stealer is supposed to be their freckly young son S.J. (Jae Head), but he's too impish and precious by half. Watching the kid put Big Mike through a rigorous training regimen, assemble a recruiting-highlights disc, and negotiate with high-powered college coaches (Nick Saban, Lou Holtz, Phillip Fulmer, Tommy Tuberville, and others play themselves) is reminiscent of Timothy Mouse leading around Dumbo.

Kathy Bates makes a late appearance as a miracle tutor. She has the best accent in the cast. Then again, she is a Memphis native.

However obvious, The Blind Side is touching - despite its habit of dropping major character notes into the melody without warning. For instance, Leigh Anne suddenly starts spouting pieties in her final voice-over.

Praise the Lord and roll the credits.EndText

Contact staff writer David Hiltbrand at 215-854-4552 or dhiltbrand@phillynews.com. Read his recent work at http://go.philly.com/daveondemand.