OK, Clayton's firm is representing a company called uNorth that makes fertiliser which has inadvertently poisoned farmers. They know they're in the wrong. Clayton's friend is the lead defence lawyer for uNorth, defending them against the lawsuit.

He finds the smoking gun evidence and uNorth kill him for it, then try to kill Clayton. He gets the executive of uNorth to admit this and blackmails her into giving him £10 million.So you think he's taking the money and running, but then he turns around and tells her that he's wearing a wire and she gets arrested, so it's a happy ever after ending.

The credits roll over him sitting in the back of a taxi that's just driving around. Then you realise Clayton's law firm will go bankrupt due to unpaid legal fees, and he'll be out of a job. So in reality, he's made things much worse for himself, but he has justice for his friend.