Movies based on true stories are often compelling. When a story like Flash of Genius features an underdog who tumbles a corporate giant, it can be a real winner at the box office.

Inventors frequently get their ideas on the spur of moment. For engineer and college professor Robert “Bob” Kearns (Greg Kinnear), this happened one day while driving his family in the rain. As the rain pattern changes from light to a downpour, he’s annoyed because the windshield wipers only have one rhythm. After a few late nights in the basement spent studying the continuous blink of his eye, Robert invents a prototype of intermittent windshield wipers.

Excited by his idea, he joins forces with his friend Gil Previck (Dermot Mulroney) -- and the two get their foot in the door for a meeting with deal makers at Ford. Envisioning he’s found the mother load and that his wipers will be put on every car in America, Bob becomes very cautious at this meeting. He parks the car yards away from the team there and refuses to let them look under the hood.

After playing tug-of-war, a Ford exec verbally concedes they indeed want Bob’s design. They decide on a price, but tell Bob they need a working model to send to Washington for safety approval. Bob agrees but insists he will be the manufacturer.

While Bob is ecstatic about this deal, his wife Phyllis (Lauren Graham) has been down this road too many times. She’s more involved in seeing that their six children have food. Bob, however, proceeds to lease a building where they will make the wipers. Shock hits Bob like a hurricane when Gil tells him Ford no longer wants his invention. Sometime later while driving in the rain, Bob can’t believe his eyes when he sees his wiper design on a passing car.

SPOILER ALERT 

A long legal battle ensues. Years pass, friends step aside, greedy lawyers (Alan Alda) come and go, but Bob refuses to be silenced about his injustice. His family hovers on the brink of desperation when Ford finally offers a pittance to keep Bob quiet. His refusal pushes his wife and kids from the home, and Bob is left on his own for years as he continues to pursue justice.

While Flash of Genius is uplifting -- even causing the audience at the screening I attended to stand and applaud -- it’s also gloomy. Watching Bob give up his family, even though later his older children step up to help him when he chooses to represent himself in court, is truly sad. One has to wonder if he should have taken the multi-millions Ford offered at one point instead of holding out for their admission of guilt. The real facts of this case are especially interesting in light of today’s distrust of the firms that hold our future in their shaky hands.

Director Mark Abraham (Children of Men, Tuck Everlasting) handles this subject well, and that may be the reason the movie ends up being so engaging. Building a story around corporate injustice, patent laws, and the span of years it takes for one to actually get a case like this into the courtroom, could have resulted in a very dull movie. While some of the court proceedings do appear near the end of the film, that’s also the payoff, or as some see it, the real end of the road.

This movie wouldn’t be half as interesting without Kinnear’s stellar performance. Fans are used to seeing his comedic side (Ghost Town, Matador), but in Flash of Genius he allows his character’s small bit of humanity and desperation over injustice to keep the man’s head barely above the quicksand. That’s what keeps viewers hanging on until the end.

(Released by Universal Pictures and rated “PG-13” for brief strong language.)

Review also posted at www.reviewexpress.com.