this article gives more details of the story and Zac will be Kyle McAvoy.
Zac Efron Stars In John Grisham's The Associate
you can get a hardcover book on Amazon for under $4.00 and read reviews, but they are spoilers. One reviewer said there is no ending so he didn't like it, the other loved it?
on this site skip past the plot info because it tells the entire story, but the second half, the reviews are the same as other reviews I've read. The end fizzels and same old plot lines. Maybe that is why they need some rewrites, everyone says the same things. Warning, skip past the plot section if you don't want the entire story, the reviews are not spoilers.
some spoilers in plot review
http://en.wikipedia.org/wiki/The_Associate_(novel)