It wasn't his favorite scene when he wrote it, nor when he shot it, but when Bill Mikita saw "Chasing 3000'' on the big screen, the sight of himself, his brother and his grandfather driving to a Pirates game got to him.

"It was very emotional to be in the car again with my grandfather,'' Mr. Mikita said.

The movie, playing at the Harris Theater, tells the story of a pair of teenaged brothers who travel cross-country in the fall of 1972 to see Roberto Clemente get his 3,000th hit. The older brother's an athlete, the younger brother suffers from muscular dystrophy.

It's loosely based on the Mikita brothers; Bill and his younger brother Stephen, born with spinal muscular atrophy, grew up in Steubenville, Ohio. They never had to travel much more than an hour to get to Forbes Field or Three Rivers Stadium, but the lengths that Bill Mikita went through to create this film make its story line -- a couple of kids journeying 2,400 miles in three days -- seem like a walk in the park.

Mr. Mikita, 55, a Cincinnati lawyer, explained it all to me Friday afternoon as we sipped soft drinks in the bar of the Renaissance Hotel. He'd just arrived in town with his wife, Pattie.

Wearing a Pirates ball cap and a sports jacket over a Clemente T-shirt, he had a nervous habit of tying and re-tying the laces of his sneakers as his story flowed. He started writing screenplays 20 years ago, giving himself a Los Angeles cell phone and using his cousin's L.A. address because nobody in Hollywood was taking an Ohio lawyer seriously.

"I out-illusioned the illusionists,'' he said.

He wrote the script for "Chasing 3000" in 1999 and, after many revisions, it was filmed here and in Los Angeles in 2005 with a cast that includes Ray Liotta and Rory Culkin. For the sake of art, the story of the bond between brothers is told as an epic crossing of America.

The real story may be even more powerful. Steve, in a wheelchair since he was a boy, was always told by his father, "You're still better off than your immigrant grandfathers.''

Why? Because he could pursue an education. Bill says his father wept uncontrollably at Stephen's high school graduation "because as a young father, he never thought he'd see that day.''

Anything beyond that would have been gravy, Bill said, but his brother excelled. Stephen became the first wheelchair freshman at Duke University, and for the past 28 years has been an assistant attorney general in Utah.

I called Steve in Salt Lake City and asked him what he thought of his brother's movie.

"It captures, I believe, a sweet dynamic that has always pervaded our relationship,'' Steve, 54, said. "Billy had this uncanny ability -- I'd call it a gift -- to make boyhood games accessible so we could engage in them and enjoy them on an equal footing.''

Some of that is in the movie, and I wondered while watching it how true it could be. But over the phone, Steve painted scenes even more vivid: two boys in the driveway after dinner, seven nights a week, playing Wiffle Ball, Steve pitching, and Billy announcing the games in the voice of Bob Prince and assuming the stance of each Pirates batter in turn; Steve waiting in a sandlot end zone for Billy to hit him with a touchdown pass, which he did; Billy coming to the hospital in the worst of times to talk baseball with his kid brother.

"He took me out of the moment and expanded my view and gave me hope,'' Steve said. "To this day, we talk to each other twice a day.''

The older brother has some selfish moments in this movie, but Steve says that's not his brother. "Billy never once resented me.''

Telling you his favorite scene would give away the ending. But there's a moment where the older boy decides to stay with his brother in an Ohio hospital rather than go see Clemente chase that monumental hit.

"That scene is emblematic of the kind of selflessness Bill has,'' Steve said. "The movie is about a baseball hero, but the story behind the movie is really about my hero, my brother.''

"Chasing 3000'' is playing at the Harris, 809 Liberty Ave., at 3 p.m. today, at 7:30 p.m. Monday through Wednesday, and at 5:30 and 8 p.m. Thursday.