It's in the basement where Kearns figures out a way to arrange Radio Shack transistors and capacitors in such a way as to yield an intermittent stroke, one that can be adjusted to variable speeds (something that stumped the best engineers in Detroit).
He wants to manufacture and assemble the device himself, so he incorporates, raises money and outfits a building to do it. But when he enlists Ford as a customer, Ford does an end run around Kearns, not to mention patent law, and pretends the invention is its own.
Kearns sues, of course, and "Flash of Genius" sets up as a typical civil-action yarn - enter Alan Alda as the crusading plaintiff's lawyer. But Kearns, it turns out, is not Fred MacMurray, and this is no routine legal saga. Kearns has bouts of mental instability, and even when completely lucid, he's too strident to work collaboratively with settlement-minded lawyers.
He's the one plaintiff who's sincere when he says he doesn't want money - he turns down handsome offers - because he wants an apology. This makes Kearns a hero among other inventors, but nearly destroys his family. His wife (Lauren Graham) drifts away, his children wonder if his priorities are straight.
One of the interesting things about "Flash of Genius" is that it does not attempt to tidy all this up. Kearns stands on principle, but his actions are destructive to people he loves, and there is no attempt to put a bow around it.
And I think if Kinnear were a more substantial actor, he might have drawn more emotion out of this conflict. One is dogged throughout "Flash," however, by the suspicion that Kearns was by nature more prickly and combative than the agreeable, genial Kinnear can suggest.
He's a good enough actor, though, to handle the plum bits. When the case finally does yield courtoom scenes, he aces them, helping "Flash of Genius" deliver on its promise of timely, underdog appeal. *