A ruthlessly ambitious farmboy connives his way to the top of the Oklahoma oil business during its early boom days. In the end, after years of backstabbing and dirty dealings, he must fight the enemies earned over a lifetime to hang on to his empire.

What Richiev said.

A protagonist should never be "hanging on" to anything. He's grasping for something more than what he has, struggling for something in the future (objective goal) that he doesn't have in the present.

I usually helps if a lead character has a goal. Hanging on is a goal but not a very pro-active one, is there another goal you could use in your logilne for the lead character?

I just noticed that I used "it's" instead of "its". My bad. I can't figure out how to correct it.